Breaking new ground

for juniper
A management handbook for lowland England
 Contents
Purpose and scope 5
Lowland juniper – the facts 6
Conservation status and distribution 6
Habitat 7
Wildlife dependent on juniper 7

Without
Identification and life cycle 8

action
Conservation challenges and solutions 9
The factors underpinning regeneration 10

nowjuniper
Site assessment 12
Management options 14
Habitat restoration 14
Juniper restoration management flowchart 15
Scrub clearance 16
Bare ground creation 17
Minimising browsing 20

faces
Seedling surveys 23
Enhancing germination 24

extinction
Reinforcement and reintroduction 26
Propagation, planting and protection 30
Monitoring and aftercare 34
Documenting 34
Appendix 1: Step-by-step guide to seed processing 36

across Appendix 2: Propagation protocol for subsp. hemisphaerica

Useful references
37
38

much
ofthe
Key contacts 39

English
Written by Tim Wilkins and Dr Jenny Duckworth
This publication would not have reached fruition without its many
contributors. Particular thanks are owed to Lena Ward, Jonathan Crewe,

lowlands
Rachael Arden, Julia Carey, Barry Clarke, Stuart Corbett, Nicky & Richard
Gould, Alistair Griffiths, Penny Jones, Shelagh McCartan and Chris Trimmer.

50years
We are indebted to landowners, site managers and propagators who have
deftly turned management theory into reality and in doing so helped

within shape this guide. In addition, the following companies have given much
appreciated advice at no cost: the Caledonian Tree Company, Cheviot Trees,
Petersfield Growing Mediums and Trees Please.
Cite as: Wilkins, T.C. & Duckworth, J.C. (2011). Breaking new ground for juniper
– a management handbook for lowland England. Plantlife, Salisbury, UK.land.
Plantlife, Salisbury, UK.

Juniper has declined across Britain but the

problem is particularly acute in the lowlands, We are Plantlife
where it has been lost completely from 9 The UK’s wild plants have been marginalised and taken for
of its 27 lowland vice-counties, including granted for too long. Wild plants clean our air and water,
Bedfordshire, North and South Essex, North provide food and shelter for our insects, birds and animals and
Devon and North Somerset. Populations that
will be critical in the fight against climate change.
are still surviving in the Chilterns, Sussex
and Wiltshire have shown declines in juniper
abundance of 84%, 69% and 44%. Many Plantlife is the organisation that is speaking up for nation’s wild
colonies have dwindled to such an extent that plants. We work hard to protect wild plants on the ground and to
they are functionally extinct. build understanding of the vital role they play in everyone’s lives.

Front cover photograph: Calstone Down, Wiltshire.

© Sharon Pilkington, Vegetation Survey & Assessment
02 Foreword Breaking new ground for lowland juniper 03
 Purpose and scope
This guide contains detailed advice to aid
the recovery of juniper (Juniperus communis
subsp. communis) across the chalk and
limestone country of lowland England.
Plantlife has been piloting a series of management
techniques with project partners to find out the best
ways of triggering regeneration and rehabilitating
functionally extinct colonies. Although these
trials are still ongoing, we hope this guide will
equip conservation practitioners, land managers
and voluntary groups with the information
they need to stem the wholesale decline of the
species across southern England. In the absence
of wider landscape-scale processes ushering in
a whole new generation of juniper, clusters of
small scale restoration projects have potential
benefits beyond the level of individual sites.

This publication forms part of a two-year

project ‘Saving England’s Lowland Juniper’,
funded by Natural England, Biffaward and
Buckinghamshire County Council.
The guide addresses the first lowland BAP action (2008) for juniper,
namely: bring research together to establish a detailed management
protocol. In so doing, it is hoped the remaining lowland BAP actions
will be achievable:
• Apply [the protocol] to key sites within core areas
• Restore and expand appropriate habitat
• Ensure grazing is at appropriate levels on all sites
• Establish ex-situ seedbank to reinforce highly isolated and edge-
Starved of light, these of-range single-sex populations with re-introductions where
appropriate
mangled skeletons of For information on managing juniper in upland situations, please
juniper sit beneath a refer to the booklet entitled ‘Managing Uplands for Juniper’ which is
available for download from the Plantlife website, or in hardcopy from
dense canopy of beech. Plantlife’s head office.
© Tim Wilkins/Plantlife

Breaking new ground for lowland juniper 05

 Norfolk

Lincolnshire
Habitat
Shropshire
West Midland

Cambridgeshire Juniper can be found growing on a wide variety of soil

Northamptonshire
Worcestershire
Suffolk types and topographies but in lowland England today it
Warwickshire
Bedford chiefly occurs on chalk downland or limestone grassland.
Herefordshire The grassland communities that support juniper (Box 1)
central are frequently species rich themselves, containing other
Bedfordshire
Hertfordshire
threatened plants such as wild candytuft, musk orchid
Gloucestershire Buckinghamshire and pasqueflower. These wild flowers stand to benefit from
Oxfordshire
Monmouthshire Essex habitat management for juniper.

Other typical habitats include: ancient trackways, paths

Swindon
S.Gloucestershire
London area
and waysides, disused quarries, cliff faces, earthworks and
West
Berkshire
rarely heathland.
N.Somerset
BANES
Wiltshire Surrey Where scrub or young woodland have colonised, juniper
Somerset Kent will slowly die out. Ironically, its prickly foliage may
Hampshire
hasten woodland development by acting as a nurse
West Sussex
tree for other species – e.g. yew. At some Chilterns sites
East Sussex juniper has been lost under beech although this may be a
© Photo credit
consequence of historical plantations. Pasqueflower

Dorset
post 1990 species records
Isle of
Wight pre 1990 species records Box 1. Lowland plant communities
The National Vegetation Classification communities listed below reflect the diversity of calcareous
Figure 1. Juniper decline across grassland habitat that juniper inhabits. Remarkably, only CG2 and CG7 typically feature bare ground
lowland England – pre-1990 sites in
red; 1990-2010 sites in blue (based on which is considered a prerequisite for juniper seedling establishment. The other communities may
1km square and 100m square records). therefore be sub-optimal for recovery.
Derived from MiniScale by Ordnance
Main lowland grassland communities supporting juniper:
Lowland juniper – the facts
Survey. Reproduced from Ordnance
Survey digital map data. © Crown • CG2a Festuca ovina – Avenula pratensis grassland, Cirsium acaule – Asperula cynanchica sub-
Copyright 2011. All rights reserved.
community
• CG2b Festuca ovina – Avenula pratensis grassland, Succisa pratensis – Leucanthemum vulgare sub-
Conservation status and distribution community
• CG3a Bromus erectus grassland, typical sub-community
Along with Scots pine and yew, juniper is one of only three conifers native
• CG3d Bromus erectus grassland, Festuca rubra – Festuca arundinacea sub-community
to Britain. Although a long-lived perennial, in southern England there are
• CG5a Bromus erectus – Brachypodium pinnatum grassland, typical sub-community
very few sites where juniper is regenerating successfully.
• CG7 Festuca ovina – Hieracium pilosella – Thymus praecox/pulegioides grassland

Juniper’s lowland headquarters lie in the South Aston Rowant in the Chilterns is the only other SAC
Wessex Downs, where it is particularly abundant primarily designated for juniper scrub in southern Wildlife dependent on juniper
on the military ranges of Bulford and Porton Down. England. Elsewhere juniper occurs more sporadically Juniper is almost a habitat in its own right, and its stems and branches can support a range of
These two areas support the largest remaining across the chalk and limestone, where the majority supporting an impressive range of wildlife, including lichens and bryophytes.
populations in southern England, with thousands of good populations are either designated SSSIs or some species that could not survive without it.
of bushes each, and are considered to be the best NNRs. Typical hotspots are the Cotswolds, Chilterns, Juniper berries and shoots provide a food source for Bare ground around juniper can attract a variety of
remaining examples of lowland juniper scrub on and the North and South Downs (Fig. 1). wild birds and mammals, especially during autumn early successional plants and wildlife. Species such
chalk. Their inclusion in the Salisbury Plain Special and winter months and it supports over 50 insects, as kidney vetch and horseshoe vetch are important
Areas of Conservation (SAC) gives them formal Owing to its BAP status, juniper is a Species of such as the juniper shield bug, juniper aphid and food plants for butterfly larvae, with the former the
recognition under the EC Habitats Directive Annex I Principal Importance in England (S41 of NERC Act juniper carpet moth. Juniper also provides ideal sole larval food plant of the small blue – a Species
habitat: ‘Juniperus communis formations on heaths 2006). It is currently listed as ‘Least Concern’ in The habitat for spiders. Studies show that the larger of Principal Importance in England (S41 of NERC
or calcareous grasslands’. Vascular Plant Red Data List for Great Britain but the populations of juniper, the greater diversity of Act 2006). Similarly, butterflies that require a short
this is on account of its long lifecycle and relatively insect species. In addition, over 40 species of fungi sparse turf stand to gain, e.g. the Near Threatened
gradual decline throughout Britain as a whole. are either entirely or partially dependent on juniper, silver-spotted skipper.

06 Lowland Juniper - the facts Breaking new ground for lowland juniper 07
 Identification and life cycle Conservation challenges

© Pat Woodruffe
and solutions
With the exception of a small population of subsp.
hemisphaerica on the Lizard peninsula in Cornwall,
all lowland populations comprise subsp. communis -
hereafter simply referred to as juniper. Taxonomically, After the last Ice Age, vast stony landscapes relatively free
these subspecies may be relegated to varieties in future. of wildlife were commonplace, providing ideal conditions for
juniper to flourish. There have since been pulses of regeneration
Juniper is unusual in that it has a variety of growth forms, across the lowlands linked to complex changes in land use. Most
ranging from prostrate to columnar. Upright bushes can recently was in the mid-1950s, in the wake of the Myxomatosis
reach four metres or more in height. Juniper’s foliage is outbreak, when the sudden drop in rabbit numbers led to the
composed of small and densely packed prickly needles that emergence of a whole new generation of bushes. The majority of
junipers in the south today owe their existence to that event. LITTLE OR
grow in whorls of three. Close up, a whitish stripe of stomata NO BROWSING
(sometimes two stripes) can be seen running down the upper
Today’s heavily managed countryside
side of each needle (Fig. 2).
has little in the way of suitable habitat
for juniper. Annual cycles of grassland BARE GROUND
From a distance, juniper can be confused with yew or gorse
management conflict with its reproductive
but yew is generally a larger tree with comb-like shoots
strategy and, despite its prickly foliage,
composed of soft, dark green needles. Female yews carry
juniper is often damaged by livestock,
Figure 2. The distinctive stomatal stripes on upper red ‘berries’ in the autumn. Gorse is a grey-green shrub with
rabbits and deer, with its seedlings
sides on juniper needles. distinctive yellow flowers for most of the year and its spines CONSERVATION MANAGEMENT
particularly palatable.
Figure 3. Male flowers cones in May lack the white stripes.
Top picture – pollen sacs full; Bottom – pollen sacs empty)
The problem is currently perpetuated
Be aware that there are also a great many garden varieties
by a tendency to manage conservation
and non-native species of juniper which can be confused
grasslands uniformly, resulting in a paucity LOWLAND CALCAREOUS GRASSLAND
with J. communis, particularly boundary and hedgerow trees.
of bare ground and a seasonal risk of
browsing from livestock (Fig. 4).  Figure 4. Current rarity of juniper regeneration habitat
Juniper is dioecious – its bushes are either male or female.
Female bushes are usually easy to identify because of their
small blue-black or green berries (strictly speaking cones or As lowland junipers typically live for 100-120 and mites that hollow out the seeds. At many
‘galbuli’). A lack of berries is a good but not totally reliable years, they have up to 100 opportunities to juniper sites in southern England, their impact
sign that the bush is male. Young females may be berryless reproduce successfully. If each individual is is substantial. Juniper seed can also abort
due to sexual immaturity and isolated females may fail to survived by just one offspring, a stable population during development due to false pollination
develop berries due to lack of pollination. Male bushes are will result. For this reason, and because of juniper’s by air pollutants or even dust. Fragmented
generally taller and produce minute flower cones in spring tendency to reproduce episodically, the absence populations and biased sex ratios can further
with abundant pollen (Fig. 3) that are slightly different in of seedlings at a site for a decade or more should impede pollination through distance or barriers.
appearance to those of females. After flowering, the remains not be a cause for great concern. However, today
of male cones may be seen for some time, allowing bushes to many populations consist entirely of old collapsing The transient nature of juniper seed means that
be sexed reliably. bushes which are prone to sudden die-off. Urgent it fails to form a persistent seed bank in the soil.
intervention is clearly needed at such sites. This fact alone makes revival of lost populations
Juniper has adapted to be mobile through efficient seed impossible without resorting to translocation.
dispersal. The berries on female bushes ripen two or three Although good berry years can produce
years after pollination which occurs by wind. In the autumn, prodigious quantities of seed, less than 2% Juniperus communis is declining in other parts of
berries fall onto the ground beneath bushes or are eaten may be viable. Combine this fact with the lowland Europe. Computer modelling suggests that
and dispersed by birds or animals. Migrant thrushes such ubiquitous threats of browsing, trampling, shade, its European range will contract northwards as the
as fieldfare, redwing and mistle thrush are particularly desiccation and disease, and it becomes clear climate warms, implying a greater international
responsible. Seedlings are slow-growing and take 4-9 years to why seedlings are so scarce. One study showed responsibility to conserve its populations in
reach sexual maturity. Juniper also has the facility to spread that out of 10,000 seeds, only 6 produced the UK. An emerging concern in Britain, is the
locally through layering (a means of vegetative reproduction seedlings that survived their first year. trend for increasingly mild winters which may
whereby branches resting on the soil form roots). This eventually result in a failure to break seed
appears to rarely happen on the dry soils of the south and its Poor seed viability occurs naturally in many dormancy (juniper seed requires two cold winters
significance has yet to be determined. small-seeded pioneer tree species. The to germinate). Furthermore, young seedlings
situation is, however, exacerbated by insects are highly susceptible to summer drought.
08 Lowland Juniper - the facts Breaking new ground for lowland juniper 09
The factors underpinning regeneration Another key condition is suppressed succession,
limiting the impact of faster-growing or taller
SLOW
As a pioneer species, the proximity of bare ground species outcompeting or overshading juniper SUCCESSION
appears to be the most important factor responsible during its development from seedling to
for seedling establishment. Areas that remain reproductive adult. Succession is naturally
continuously open with plentiful bare ground are slowed through a combination of impoverished
much more likely to support seedlings. Episodes skeletal soils and naturally eroding or steep
of intense bare ground creation need to be slopes. Preventing soil enrichment is the key to
followed by long periods of little or no disturbance. suppressing succession. BARE MINIMAL
Traditional activities such as droving, shepherding, GROUND BROWSING
or occasional cultivation, would have created such High light levels are clearly associated with
conditions. Similarly, ancient trackways, earthworks juniper establishment. Although one study
and old quarries provided ideal habitat and are The intensity of rabbit and deer has shown successful growth in 20% daylight,
typical juniper haunts today (Table 1). Currently, browsing in combination with livestock higher light levels tend to yield higher growth
regeneration is largely confined to a few roadside levels is crucial in determining seedling rates. Seedlings growing directly beneath parent
bushes will perish in persistent deep shade. MEDIUM-HIGH
embankments although some of these colonies survival and growth. Browsing levels LIGHT LEVELS
originated as introductions (Fig. 5). may need to be low for 10 to 15 years
before seedlings are sufficiently robust. The diagram in Fig. 6 summarises the interplay
of these conditions. Note that not all need be PERSISTENT OPEN BARE GROUND
true at the same time – e.g. a period of high WITH LOW BROWSING PRESSURE
grazing pressure creating bare ground may be
followed by little or no grazing.
Figure 6. Key regeneration conditions.

Figure 5. Natural colonisation on a Wiltshire roadside bank © Pat Woodruffe

Habitat Site examples Causal factors

Downland and grassland Porton Down (Wilts) • Fluctuating rabbit population –
Bulford Down (Wilts) e.g. post-myxomatosis (1954-5)
Rodborough Common (Gloucs) • Controlled grazing (poaching)
• Terracettes on slopes
(e.g. sheep paths)
• Protected sites
Old/ancient quarries Noar Hill (Hants) • Abundant bare ground
Painswick Beacon (Gloucs) • Steep slopes
• Cycle of abandonment and re-use
• Minimal grazing when quarried
• Protected sites
Waysides, ancient routes and Aston Rowant (Oxon) • Long-standing use
earthworks Stockton Down (Wilts) • Route changes (cycle of abandonment
Winterbourne Downs (Wilts) and re-use)
Roundway Down (Wilts) • Stock movements/funnelling (poaching
Fleam Dyke (Cambs) intensity gradient; minimal browsing)
Figsbury Ring (Wilts) • Sunkenways and slopes (natural erosion/
soil creep)
• Protected sites
Wild animal tracks, burrows Stockton Down (Wilts) • Badger setts
and diggings • Habitual animal tracks
Table 1. Principal lowland juniper habitats, with
factors considered responsible for juniper’s persistence.

10 Conservation challenges and solutions Breaking new ground for lowland juniper 11
Site assessment Box 2. How to assess seed viability
The cut-test is a reliable, albeit destructive, way of determining seed viability. It can be done in the
Before management options can be considered, some key facts about the field but accurate dissection and examination is best done off site.
site and any surviving juniper must be known.
Equipment
Site information needed: Locking knife, cutting board (e.g. back of old clipboard), hand lens (x10), notebook and pen. Alternatively,
• grazing levels if checking berries off site: sample bags or envelopes, a low-powered binocular microscope, scalpel and – if
• pressure from rabbits and deer storage required – use of a domestic fridge.
• amount of bare ground (%)
• location of good juniper habitat (open, unshaded, thin poor soils, Collecting
• Seed viability can vary a great deal between individuals and stands.
sloping, pockets of bare ground)
Take small samples of berries from:
• presence/restoration potential of early successional flora and fauna
 All females for small colonies (< 30 bushes)
• proximity of ruderal infestations  At least 50% of females for medium colonies (30–100 bushes)
• proximity of mixed scrub and young woodland  At least 20% of females for large colonies (>100 bushes)
• proximity of field vole habitat (tall grassland) • Pick no more than 20 ripe berries per bush (plump blue-black berries are ripe; leave those that are green or
• location of key conservation features brown). If bushes have very few berries, collect one berry for each 10 available.
• location of key heritage features • Use a sharp knife on a flat hard surface to cut ripe berry cross-ways (equatorially),
• access routes for excavator cutting through seeds.
• management plan and long-term aims • If you intend to collect seed for propagation afterwards, keep a record of each bush’s seed viability, along
with its location (GPS or sketch map) and the availability of ripe berries.
• If collecting berries for examination later, bag and label each sample.

Examination
Population information needed
In the field, cross-sections should be examined with a hand-lens. Off site, a low-powered binocular microscope
(also refer to Seedling surveys section): is useful. If checking at a later date, store berries in breathable containers (e.g. paper bags) in a fridge.
• abundance: small colony <30 bushes; medium 30-100; large >100
Viable seed is always filled with a white/creamy interior (endosperm) – Fig. 7. If the seed is brown or hollow
For small and medium sized populations, try to record the inside, it is almost certainly unviable. Note that not all filled seeds will germinate but the test gives a good
location of every bush (use a GPS) along with the following estimation. If intermediate seed is found (e.g. incompletely filled, or endosperm slightly brown) consider these
attributes: doubtfully viable.
• sex Berries are occasionally galled by insects/mites and the seed eaten.
• age class (seedling, young, mature, over-mature, dying and dead) Figure 26 shows some types of damage and the species responsible.
• level of seed viability (Box 2)
• amount of disease/physical damage Results
• berry abundance (especially ripe berries) Calculate the mean seed viability per bush and per colony and then refer to the table below. Note that some
females may yield samples containing no viable seed.
For larger populations, take a representative sample from each
stand/colony and record:
• a centroid grid reference
• sex ratio (% of: male and female)
• age structure (% of: seedling, young, mature, over-mature, dying <10% poor
and dead) 10-40% moderate
40-60% good
When plotted on a map, the spatial distribution of bushes/stands
along with their attributes may reveal weaknesses in the population >60% very good
structure, allowing a more strategic conservation approach, e.g. by
revealing isolated single-sex stands suitable for reinforcement. Viable seed Unviable seed

 Figure 7. Typical cross-section of berries & seeds

12 Site assessment Breaking new ground for lowland juniper 13

Management options Juniper restoration management

On sites where juniper has steadily dwindled and consistently failed

KEY THREATS
to regenerate, intervention is likely to be unavoidable to secure Scrub / Woodland • heavy shading / succession
recovery. There is no silver bullet: juniper seed is slow to ripen and Juniper in mixed scrub or under tree canopy • impeded pollination
germinate, seedlings are slow growing and can take up to 9 years to • impeded dispersal

reach sexual maturity. Ex situ techniques may decrease the recovery PHASE I MANAGEMENT PITFALLS
time but aftercare may be necessary for 5-10 years after planting. • Scrub clearance • accidental damage
• Stump treatment • bushes more prone to collapse, windthrow or snow damage
All restoration projects should run for at least 10 years. • Control of re-growth • death by light shock (particularly etiolated bushes)
• increased exposure to livestock, rabbits or deer.
Habitat restoration is the key to long-term recovery, without it additional
measures such as reinforcement will prove unsustainable. Restoration
is also likely to be of far greater ecological benefit (see Wildlife KEY THREATS
Long grassland • insufficient bare ground (seedling habitat)
dependent on juniper). Where juniper colonies have poor seed viability, or Juniper in ungrazed/uncut grassland • seedlings overshaded
imbalanced sex ratios, a combination of in situ and ex situ techniques can • deer (browsing & debarking)
• small mammals (berries, seed or seedlings eaten)
be highly effective.
PHASE II MANAGEMENT PITFALLS
• Enclosure • damage by machinery or stock (especially hardy breeds)
There are three broad approaches to management: • Stock grazing or cuttng • hidden seedlings exposed to damage
(introduced or increased) • deer damage unchecked
1. Habitat restoration (facilitating natural regeneration)
2. Assisted regeneration (enhancing germination)
3. Reinforcement or reintroduction (transplanting) Short grassland KEY THREATS
• grazing animals (browsing, rubbing, trampling)
Juniper in grassland grazed by stock
Fig. 8 shows the pathways to regeneration for a range of lowland habitats. Under • insufficient bare ground (seedling habitat)
and/or rabbits • soil enrichment
each management phase is a breakdown of the steps required. Although we have
placed techniques to stimulate natural regeneration ahead of translocation, it PHASE III MANAGEMENT PITFALLS
• Controlled grazing or pinch points or • soils too rich/deep (attracts ruderals or tree seedlings)
is possible to skip or combine phases (so long as the chances of future natural ground scrapes (unsown) • insufficient seed reaches bare ground
regeneration are uncompromised). Where viable seed and bare ground co-occur, SUCCESSFUL • Seed-shelters or seedling • spiny brash piles not replenished
REGENERATION protection or grazing relaxed
we advise waiting at least three years for juniper seed to germinate (see Seedling • seed-shelters not removed after re-vegetated
• exclosures not rabbit proof
surveys) before progressing to the next phase of management. • exclosures/shelters fail to last 5 years
• lack of monitoring (annual seedling surveys)
• problems managing site long-term for natural re-gen

Habitat restoration KEY THREATS

The management sections on pages 16-25 give a broad range of Scree / Rocky ground • low seed viability
Juniper on/by unvegtated ground - • poor sex ratio / skewed distribution
options. Each option begins with a checklist of desirable attributes to • population small and fragmented
e.g. quarries or scrapes
help you determine its suitability. • single cohort of over-mature bushes
• conversion to arable or other land use
The following are additional:
PHASE IV MANAGEMENT PITFALLS
• At least one male and one female bush on site (otherwise reinforce) • Seed sown or • planting/sowing area proves unsuitable
• Average male:female ratio more balanced than 5m:1f (otherwise reinforce) SUCCESSFUL cultivated bushes planted • insufficient numbers planted/sown
REGENERATION • Seedling/transplant protection • unprocessed seed sown
• Female bushes with abundant ripe berries (if needed) • low survival rate due to poor planting
• Skeletal soils (poor and thin) • planted outside of autumn
• transplants are clones of one stockplant
• Open sloping land (unshaded) • bushes in cultivation too long
• Low risk of mixed scrub encroachment • sexes poorly mixed, or too few female bushes
• incorrect guard used for seedling/transplants
• Low risk of ruderal infestations • lack of annual weeding
• Presence or records of other important early successional species • exclosures/shelters fail to last 5 years
• lack of monitoring (annual seedling surveys)
• Other site features uncompromised (biological, archaeological, amenity, etc)
• problems managing site long-term for natural re-gen

The more of these characteristics your site possesses, the greater the likelihood
of achieving natural regeneration. Figure 8. Management flowchart for non-regenerating stands. Select main habitat type and follow steps of management phase beneath. Prevailing threats
for each habitat are listed alongside, as are potential drawbacks of each management phase.

14 Management options Breaking new ground for lowland juniper 15

Scrub clearance Bare ground creation
Suitability:
• Juniper surrounded by young woodland/mixed scrub Controlled grazing
• Grassland restoration scheme ongoing The removal of trees/shrubs surrounding Suitability:
• Low numbers of rabbit and deer juniper needs to be phased over two or more • Enclosed cattle-grazed grassland
• Livestock type/breed prefer years, rather than clear-felled in one season. • Cattle breeds that rarely browse
broadleaf scrub to juniper This should allay the risks of light shock and • Medium to large stands of male and female
collapse. Even after gradual clearance some bushes
Where the original habitat has succeeded into mixed scrub limbs may break under their own weight or • Low numbers of rabbit and deer
or young woodland, restoration is likely to take considerably through increased exposure to wind and snow • Seed viability moderate-very good (>10%)
more time and resources than on grassland. The overriding (Fig. 10). Only prune back bushes if necessary,
threat is lack of light, which causes a progressive weakening using sharp clean tools. High impact cattle-grazing during the ‘berry drop’ period
of shoots and stems (etiolation) and eventual death of
of Oct-Dec should create ideal conditions for natural
bushes. The reproductive potential of etiolated bushes is Removing the scrub barrier may expose bushes regeneration through poaching (>10% bare ground Figure 11. Controlled grazing can produce copious germination
likely to be extremely low. Furthermore, isolated females are to livestock, deer and rabbits. If goats or cover) – Fig. 11. Afterwards the site should be allowed to microsites
unlikely to receive much pollen nor attract birds to disperse hardy breeds are being used to control woody recover and extensively grazed as appropriate. Seedling Figure 12. Gateway pinch point
seed (Fig. 9). Ground conditions in mixed scrub are generally regrowth, monitor bushes regularly for browse surveys should take place annually for the next few
unsuitable for seedling establishment due to a thatch of damage. In cases of severe damage, some form years (see section below). Provided the sward will sustain
organic matter and heavy shading. of exclosure may be needed (see Protection). no permanent damage, the regime may be repeated if
no seedlings appear.
Weighing up the existing ecological value of the scrub/ After each round of clearance, a flush
woodland against that of liberating the juniper colony will of vegetation re-growth is usual. Before Some damage to adult bushes (e.g. broken branches)
determine the way forward. Where scrub is diverse and controlling this, it’s advisable to carry out a may be unavoidable. If young bushes or seedlings are
mature and juniper scattered and in low number, it may seedling survey (section below). In the absence present and cannot be protected (see Grazing exclosures)
be of greater overall benefit to translocate the colony to of grazing, an annual ‘cut and remove’ regime use another technique to create bare ground.
nearby grassland, or another open habitat, that can be may prove a good alternative but care should
managed appropriately. The relic bushes should be used be taken to avoid damaging bushes and
to donate cuttings and berries for ex situ propagation (see seedlings. If herbicide is to be used, choose
Reinforcement and reintroduction). equipment that eliminates the risk of drift. Pinch-points
Suitability:
© Pat Woodruffe
• Cattle-grazed grassland Figure 13. Poaching of ground around water trough
• Cattle breeds that rarely browse
• Small distinct stands of male and female bushes,
or satellite females
• Low numbers of rabbit and deer
• Seed viability moderate-very good (>10%)

Pinch-points are narrow gaps through which livestock

routinely pass, creating patches of disturbed ground.
They can result from natural obstructions (e.g. scrub) but
are more commonly associated with gateways (Fig.12).
At some sites, it may be possible to create pinch-points
in the vicinity of berry-clad females using fencing,
or through the strategic placement of water troughs
(Fig.13). Although places where animals congregate
or lay up tend to become nutrient enriched and have there will be a gradient of disturbance either side
higher browsing pressure, the routes to these places may that may provide suitable microsites for germination
provide ideal habitat. and growth.

Poaching is more intense where tracks are sunken or Consideration should be given to reinstating routes
bounded by banks, ditches or fences. Animals driven or that have fallen into disuse such as old drove roads
Figure 9. Surrounded by young scrub, this healthy bush is ridden along such tracks have relatively little time to and sunken ways, especially where old bushes survive.
doomed without intervention.
browse adjacent vegetation - including juniper. Although Opening up routes for public recreation (e.g. as
Figure 10. Sudden clearance of mixed scrub can lead to bush collapse. trampling may be too intense, and soil too compacted, bridleways or mountain bike trails) may offer
for juniper seedlings to establish in the track centre, a good alternative.

16 Habitat restoration Breaking new ground for lowland juniper 17

Scrapes Natural regeneration – On sites with acceptable
seed viability (average >10%), a scrape immediately
Suitability: downslope of, or adjacent to, females with ripe berries
• Wide range of habitats should be effective. Juniper seedlings have been
(grassland, mixed scrub, ex-arable) observed growing along fence lines and beneath trees
• Wide range of seed viability due to bird perching, so creating bird perches over
(depending on berry availability) scrapes may help.
• Low numbers of rabbit and deer
• Compartment extensively grazed or Assisted regeneration - Where it is unfeasible to
ungrazed for a period create a scrape adjacent to females bushes, or seed
Figure 16. Sowing seed across a scrape in Wiltshire
• Livestock type/breed that rarely browse viability is altogether poor (<10%), a good alternative
• Access for excavator is to sow the scrape by hand (Fig. 16). This has some
distinct advantages over natural colonisation because Unlike areas subject to continual erosion, scrapes will
Scrapes are areas that have been scarified by machine Large scrapes are preferable to small ones as they slow scrapes can be: gradually revegetate and can close over in as little as five
or manually (depending on size) so that no vegetation down succession and discourage herbivores by offering • sited optimally years. Juniper’s inherent slow germination and growth,
remains. They are a quick way of generating bare ground neither food nor shelter (Fig.14). Shape is generally • located to create links between isolated colonies means that seedling establishment is effectively a race
in the right place but do not persist. Careful siting unimportant but long narrow scrapes are best avoided as • sown at other times of year against time. Monitor during this period to identify
of scrapes is critical to their success. Excavators are they are less of a deterrent to herbivores and will more (although autumn is thought best) changing management needs (see Seedling surveys).
advantageous on deep soils and where arisings need rapidly revegetate. • sown with cleaned and screened seed
to be moved, but on thinner soils ploughing or power (see Enhancing germination) If a scrape has been created on heavily grazed land,
harrowing may suffice. Scrapes should be as shallow as possible to expose or there is an acute threat from rabbits/deer, it may be
the maximum amount of bare rock/stone (Fig. 15). However, this method may be subject to translocation necessary to install an exclosure fence.
Scrapes reduce the risk of berry foraging by voles and A preliminary ‘test dig’ is highly advisable to check protocols and is more labour intensive, requiring seed However, this should only be considered a temporary
- to a lesser extent – wood mice. Protecting seedlings the soil depth, which can vary over remarkably harvesting, processing (see Enhancing germination) measure – see Grazing exclosures. Seed shelters may
from small mammals may be unnecessary unless tall short distances. On areas cleared of mixed scrub, and sowing. offer another alternative.
grassland develops harbouring field voles (Box 3). stumps can be removed during scrape creation.
Soil arisings should be taken away from the scrape
site rather than bunded around the edge, or piled
close by, because topsoil may contain ruderal seed
that on flowering will seed back into the scrape.
Box 3. Small mammals – friends or foes?

© Richard Gould
© Jonathen Crewe © Jonathen Crewe Field research conducted by Plantlife over 2009
and 2010 suggests that field vole, bank vole and
wood mouse seldom impact negatively on juniper
regeneration.

No evidence was found of these species attacking

juniper seedlings nor young stems despite past reports
of damage by voles (particularly field vole). However,
voles did occasionally gnaw the bark of adult bushes.
Damage to roots by field vole was negligible but the
junipers studied rarely occurred in long grass – typical
field vole habitat. Overall, rabbits and sheep were
considered to have a much greater impact on seedling
survival than small mammals.
Figure 17. Berries de-seeded by wood mice
Both bank voles and wood mice were found to eat
juniper berries (Fig. 17) but generally only a small
proportion of those available were taken (although this
Figure 14. Created for juniper, a 400m2 chalk was expected to increase over the winter as alternative Berry foraging and caching may be beneficial to
scrape on the South Wessex Downs food sources diminished). Foraging by wood mice was juniper. Seedlings were frequently found associated
Figure 15. Newly dug, this Cotswolds limestone more intense beneath bushes that provided a close with bank vole tunnels and the caching of berries
scrape has been sown with hundreds of seeds sheltered environment. Nevertheless, seedlings were away from parent bushes may act as a means of
still noted in areas of relatively high berry foraging. seed dispersal.

18 Habitat restoration Breaking new ground for lowland juniper 19

Minimising browsing Box 4. How to install seed shelters

Seed shelters Regardless of whether shelters are to be sown or not,

installation sites will generally need scarifying or
To prevent small mammals tunnelling under and
raiding berries, it is advisable to sink shelters into the
Suitability: turf-stripping by hand (a mattock is ideal). The ground ground at least 4inches (10cm). Backfilling should
• Stock-grazed grassland (especially sheep) beneath shelters should be rocky and as far as possible help secure the shelter but anchoring posts or pins
• Small to medium fragmented juniper colonies free of vegetation and soil. Test the soil depth first may be necessary on steep slopes (Fig. 20).
• Large populations of rabbit, deer or small and choose another location if deep or rich soils are
mammals encountered.
• Wide range of seed viability (depending on berry
availability) The stripped areas will generally close over after a few
years, leaving little time for seedlings to establish.
Plantlife is trialling specially designed shelters to Natural regeneration – This is only feasible where To slow down the succession, scarify an area slightly
prevent berries and seedlings from being eaten (Fig. 18). there is a female bush in the open with plentiful ripe larger than the dimensions of the shelter (Fig. 19).
The seed shelters are made of galvanised welded wire berries and good seed viability (average >10%). Shelters
mesh (13mm - mesh size; 16g - gauge) stapled onto should be installed in autumn before berry drop,
treated timber frames. The mesh size has been carefully September being the best time. Earlier installation is not
chosen to keep out small mammals yet is large enough recommended because this will reduce the window for
to allow juniper berries to fall through onto the ground. germination and growth as the sward inside becomes a
Shelter
The shelters are hinged for flat-packing yet readily competitive threat. Assign one shelter per female bush,
assembled on site with four bolts. The tops are removable installing it in the berry ‘drop zone’ but far enough from
to aid seedling monitoring. Shelter dimensions are: the trunk base to avoid overshading. Sloping ground
120cm x 120cm x 30cm and a less conspicuous half- is advantageous as shelters can be sited further away
size version: 60cm x 60cm x 30cm. The shallow height downslope. On exposed sites make allowances for the
allows shelters to be positioned close to female bushes prevailing wind direction.
whilst not inhibiting seedling growth. Refer to Box 4 for
installation details. Assisted regeneration – Where there is a lack of
suitable installation sites beside female bushes, or seed
viability is universally poor (<10%), shelters can be sown
by hand. This has some distinct advantages over natural
colonisation because shelters can be:
• sited optimally
• located to create links between
isolated individuals/groups Turf-stripped ground
• sown at other times of year
(although autumn is thought to be optimal)
• sown with cleaned and screened seed
(see Enhancing germination)

© Jonathen Crewe

© Jonathen Crewe
However, this method may be subject to translocation
protocols and is more labour intensive, requiring seed
harvesting, processing and sowing. The large Plantlife
shelters were sown with 50 seeds and the small shelters
with 15 but optimum sowing rates are not yet known.

Shelters should be monitored at least annually (see

Seedling surveys) and remain in situ until there is
no appreciable bare ground left (usually after 3 to
4 years), after which they should be removed and if
possible reused. Seedlings may need a further period of
protection, depending on levels of browsing, trampling,
etc until they are sufficiently robust (see Monitoring
and aftercare). Field voles may pose an additional risk
Figure 18. Large seed shelter where seedlings occur in tall grass (Box 3).
Figure 19. A good installation on de-turfed ground Figure 20. Shelter with anchoring posts
beneath adult female

20 Habitat restoration Breaking new ground for lowland juniper 21

Grazing exclosures Box 5. A less obtrusive approach to management
Suitability:
• Stock-grazed grassland Piles of spiny brushwood create a less conspicuous barrier to herbivores and can be used in two ways:
(especially cattle, ponies or horses)
• Small to large juniper colonies (clustered bushes)
• Large populations of rabbit or deer • Barriers around the bases of productive female or
• Wide range of seed viability male bushes, mitigating browse and bark damage

© Jonathen Crewe
(depending on berry availability) (Fig. 23). This approach has been successfully
• Frequent bare ground pockets, demonstrated at a site in Buckinghamshire,
or pre-prepared scrape Well-sited juniper exclosures should remain beneficial however seedlings may appear directly
• Absence of tall grassland in vicinity for about 5 years, after which they gradually become beneath parents.
counterproductive without some form of vegetation
Fenced exclosures (Fig.21) can be expensive and are control. Once the exclosure vegetation has closed over, • Loose mats or rings of spiny brash on open bare
often reviled as a last resort but on heavily grazed sites there are several options: ground (scarify or deturf if necessary). Seed or
they provide an effective way of facilitating natural • remove the exclosure completely berries can then be cast within, or bird perches
or assisted regeneration. To be successful, they need • allow grazing animals occasional access (lightly created above. Note that juniper will not establish
careful siting, monitoring and maintenance. graze) in deep shade, so avoid making mats too dense
• manually weed - carefully strip/cut back overgrowth
As with shelters, areas with the thinnest poorest soils (moss carpets can be scratched out with a spring-tine Refer to the suitability criteria given for seed shelters.
and abundant bare ground should be chosen. At least rake) Brash piles should be checked and replenished from
one productive female (with good seed viability) and time to time to remain functional.
ideally a mixed-sex group with several females should Seedling junipers will probably need guards installed
be included. If seed viability is universally less than before exposing them to grazing animals (see Figure 23. Encircled by thorns, this young bush
10%, enclosing a seeded scrape will likely yield greater Protection). If tall grass dominates, there may be an is afforded greater protection from rabbits
success. additional risk from field voles. Maintaining a shortly
mown strip around the outside of exclosures may help
Several small exclosures are usually preferable to a deter voles.
single large one. The smaller size makes them easier to
check and maintain, and if a fence is breached not all Fenced exclosures, shelters and guards may be Seedling surveys
junipers will be at risk. Small exclosures can however be considered eyesores or an unwanted expense. A cheap
Seed usually starts to germinate in the second spring Keep a record of exact numbers and locations; if time
easily forgotten (Fig.22). and more natural alternative is given in Box 5.
after reaching the ground due to the need for two allows note height and condition too. Shelters, guards
winters to break seed dormancy. However, earlier and exclosures will help mark spots on the ground but
germination is possible depending on when seed a GPS unit is useful back-up and a means of digitising
matured on the bush. Germination peaks after about locations. Photographs are also a helpful reminder and
2.5 years but may continue for up to 5 years. provide a simple way of monitoring changes in the sward.

The best time to look for seedlings is in May Monitor seedlings at least annually. Growth
or June although they can be inconspicuous rates vary considerably but typical maximum
in grassland so a thorough ‘hands and knees’ seedling heights are: 5cm in the first year, 14cm
search is advisable (Figs. 24 & 25). in the second and 23cm in the third.

Figure 24. Prime seedling habitat © Richard Gould

Figure 25. Vigorous seedling

© Jonathen Crewe
Figure 21. A sown exclosure plot on the
Hampshire Downs
Figure 22. Juniper is entombed in this
long-forgotten exclosure

22 Habitat restoration Breaking new ground for lowland juniper 23

Enhancing germination Box 6. Top tips for collecting berries

Equipment / materials: collecting bags or containers, work gloves, eye protection (advisable), ‘berry
catcher’ (e.g. upturned umbrella, bucket, tray or ground sheet), GPS, notebook & pen.
Berry harvesting Seed processing
Only ripe berries should be collected, which are smooth, By removing the flesh of the berry and cleaning the • Keep a record of each parent bush (GPS grid ref, • Collect from as many different females
plump and purple-black in appearance. Harvesting is seed, the rate of germination can be more than doubled. age class, approximate number of berries taken, as possible
best carried out between late-September and the end Germination is thought to be inhibited by chemicals in by whom); these details can be databased off site • Ignore sickly looking bushes and those with
of October: too early and some berries will be unripe; the fruit pulp, an adaptation to aid dispersal by birds • Label containers/bags to cross-reference with abundant insect/mite damaged berries
too late and ripe berries will have been eaten by birds and animals. Juniper tends to produce a high quantity of written record • Avoid green or brown berries or those that are
and other wildlife. Genetically, it is better to collect a dead seed, although this can be readily removed through • For large populations, it may be impractical to blue-black wrinkled
few berries from a large number of bushes than many flotation. Appendix 1 gives a step by step guide to record every bush, in which case, keep separate • Whilst on site, remove invertebrates
berries from a single individual. Look out for insect/ processing seed and Fig. 29 shows the finished product. collections for each stand or colony and debris from the container
mite damaged berries and avoid collecting these (Fig. • Collecting berries one at a time is impractical. - e.g. through winnowing.
26). If there are few female bushes, or few berries on the A good alternative is to brush off berries with a • Process berries to remove seed as soon as possible
bushes, harvest no more than 30% of the total available gloved hand while holding a container beneath (Appendix 1)
as they are a good food source for wildlife which (Figs. 27 & 28, options listed above).
consequently disperse the seed. Box 6 gives further
harvesting tips. Figure 27 Figure 28

Seed viability is easily checked in the field for each

female or a representative sample of the population (Box
2). The results can be useful for estimating the number
of berries required for assisted regeneration. As a guide,
a one litre container holds approximately 4000 berries,
with each berry containing one to three seeds (rarely
four). However, the amount of viable seed may be a small
fraction of this. Figure 29. Fully processed seed

Figure 26. Insect and mite damage to juniper berries. Image kindly supplied by Lena Ward.

Storing seed and stratification Sowing

Juniper seed can be readily stored without degrading. Sowing should be undertaken in the autumn before the
Ensure the seed is dry (moisture can cause mould), onset of winter. Although seed can be sown immediately
Juniper seed chalcid before putting in a loosely-tied plastic bag and then in a after processing, without stratification germination will
domestic fridge (about +4oC). Stored in this way, the seed normally take at least 18 months.
deteriorates very slowly (over a number of years).
Juniper shield bug The amount to sow will depend on the size of the
also on other garden Juniper seed is classed as ‘deeply dormant’ because scrape but also seed availability. As a rule of thumb we
Conifers in the UK it will only germinate after experiencing a series of suggest sowing up to 30 viable seed per sq m. Only a
Eriophyid gall mite most serious in south seasonal temperature changes. It is possible to shorten small fraction of this is likely to germinate and survive
the dormancy period by emulating the seasons. the seedling stage. Appendix 1 includes a guide to
Preliminary results from Forest Research trials suggest measurement.
Juniper scale that seed subjected to two weeks of warm temperatures
Introduced in UK followed by an indefinite cold period triggers the highest A record should be kept of the sowing date, the number
germination rate in just 40 weeks. In the absence of sown, and exactly locality (use a GPS). Pass this
incubation facilities, similar conditions can be recreated information to your local biological records centre or
using a cellar for the warm period and a fridge for the cold. the county botanical recorder (Botanical Society of the
British Isles), or Plantlife.

24 Enhancing germination Breaking new ground for lowland juniper 25

Reinforcement and reintroduction Site reintroduction should only be
considered once the causes of loss have
Attempts to trigger natural regeneration can fail for a variety of reasons
such as imbalanced sex ratios or colony fragmentation impeding pollination. been identified and resolved. In cases
If restoration is impossible, or attempts have consistently failed, it may where the original habitat has been
be appropriate to reinforce or reintroduce colonies. Such action should altogether lost, severely damaged or
only be taken as a last resort and guided by policy - see JNCC (2003)
is beyond restoration, an alternative
under Useful References. Ultimately the colony created should be of
sufficient size to be self-sustaining under the right management. nearby site should be sought.
Early consideration should be given to the
suitability of habitat at the intended planting
Translocations can generally be prioritised as follows: site. Areas recently cleared of mixed scrub/
woodland are unsuitable unless woody re-growth To help you determine whether reintroduction or
1. Reinforcement of a small colony (less than 30 bushes) reinforcement is suitable for the recipient site, the
has been successfully controlled, or a scrape
to address an imbalanced sex ratio, rejuvenate age sections below begin with a checklist of desirable
has been created. Potentially suitable planting
structure, or link isolated stands (inter-planting) attributes. The following are additional to these:
habitat includes: stock-grazed grassland, ex-
2. Creation of a neighbouring colony when conflicting
arable fields (impoverished soils only) and • Reasons for past decline identified and resolved
conservation interests mean that suitable habitat cannot
disused quarries (with compatible after-use). • Open habitat with at least 10% bare-ground cover
be restored for an existing stand – e.g. over-mature bushes
The receptor site should be agreed by all • Extensively cattle grazed most of the
trapped in woodland of high conservation value
stakeholders well in advance of planting out time; occasional mob-grazing feasible
3. Reintroduction to a recently extinct site
where suitable habitat exists • Low/controlled browsing pressure
Propagation takes time: cuttings will need at from rabbits and deer
4. Reintroduction to a historical site where suitable habitat exists
least two years growth before they are ready for • 10 year aftercare plan feasible
5. Creation of a new colony within juniper’s known historical range
planting; seeds can take five or more years due to • Skeletal soils (poor and thin)
their inherent dormancy. Populations with low seed • Open sloping land (unshaded)
viability (Box 2) are better suited to propagation • Low risk of mixed scrub encroachment
Translocations need careful planning to be from cuttings. Cuttings are quicker growing but • Lack of tall grassland in the vicinity
can have high failure rates and result in clones
successful and to avoid damaging features (field vole habitat)
of parent bushes. Seedlings tend to have greater • Presence or records of other important
of the donor site (the source of cuttings, genetic diversity but seed is slow to germinate early successional species
berries or transplants) and the receptor site and seedlings slow to develop. As neither method • Other site features uncompromised
(the intended planting area). Although a is straightforward, higher success rates may be (biodiversity, archaeological, amenity, etc)
attained through a specialist tree nursery.
licence from Natural England is not required
to collect seed or cuttings from juniper in For larger projects a combination of plants from
the wild, SSSI consents may be needed for cuttings and seed is probably the best strategy,
both donor and receptor sites. Permission giving tangible results early on, whilst improving
the future genetic diversity of the population.
should also be obtained from landowners.
Aim to create a colony of at least 30 mixed-
sex individuals, including any existing bushes,
as this is thought to constitute a genetically
robust population. Recovery may be expedited
by introducing a higher proportion of females –
e.g. a sex ratio of 3 females to 2 males (note that
female junipers tend to die earlier than males).

26 Reinforcement and reintroduction Breaking new ground for lowland juniper 27

 Box 7. Local provenance

Juniper is genetically very diverse. It appears the isolation of some populations has, over time, led to inherited
traits developing. Even populations a short distance apart can be genetically and morphologically distinct.
However, across subspecies communis these differences are too small to be recognised taxonomically.

There are currently two schools of 2. Under rapid climate change species will evolve. To
thought on the importance of local maximise juniper’s resilience and adaptability, small
provenance with respect to juniper. isolated populations ought to be linked and reinforced,
thereby enhancing gene flow and broadening gene pools.
1. To preserve local distinctiveness and To allay the risk of outbreeding depression (reduced fitness
maximise survival, planted juniper ought caused by crossing between two genetically distinct
to originate from material collected from populations), multiple donor sites should be used and
the same population, or in the case of re- sufficient numbers planted. Reintroductions should likewise
introduction, the nearest sizeable population. originate from material collected from multiple donor sites.

Revised IUCN guidelines on translocation are due to be published in 2011. It is hoped that the guidelines will
reconcile these opposing views and indicate best practice for both reinforcement and reintroduction.

Reinforcement Reintroduction
Suitability: Suitability:
• Functionally extinct populations (negligible • Juniper known to occur at site in the past, or
chance of natural regeneration) site within known historical range
• Population ‘repairable’ (natural regeneration • Donor population/s identified (Box 7)
possible in future) • Permissions obtained to create a colony of at
• Additional donor population/s available if least 30 mixed-sex bushes
needed (Box 7)
• Permissions obtained to supplement colony to a The decision to reintroduce a BAP species should not
total size of at least 30 mixed-sex bushes be taken lightly; consultation will be needed with
site stakeholders and a management plan in place to
As well as boosting numbers, reinforcement is facilitate long-term recovery.
an efficient means of diversifying age structure,
balancing sex ratios, linking up isolated individuals/
groups and generally enriching the gene pool.
Nevertheless it should be undertaken sparingly,
just enough to ‘repair’ the population and kick-start
natural regeneration.

Use the information gathered in the Site Assessment

to produce a planting plan. If you are planting to
improve pollination rates, take into account the
prevailing wind direction.

If existing bushes cannot provide sufficient material

for propagation (e.g. if only one sex is present), donor
material from additional site/s should be sought
- see Box 7.

28 Reinforcement and reintroduction Breaking new ground for lowland juniper 29

Propagation from cuttings Box 8. Top tips for taking cuttings
The processes of ageing in plants grown from cuttings Equipment / materials: work gloves, secateurs, cleaning solution, plastic bags, marker pen, water-
are not known. Such plants are in reality as old as filled mist sprayer, cool box/bag, GPS, notebook & pen.
those from which the cuttings were taken and they
may suffer from reduced fertility associated with older Collect over the winter (ideally before year-end but no later than mid-February). To capture the genetic
plants. For the same reason, cuttings have a distinct diversity, ideally take about 4 cuttings per bush (depending on size of cutting) from at least 30 bushes,
time advantage over seedlings in that they are already representing both sexes and the full range of growth forms. Collect extra cuttings to compensate for likely
sexually mature. losses during propagation. If there are fewer than 30 bushes, avoid over-pruning by collecting from a
neighbouring colony as well (note translocation protocols may apply).
Cuttings usually take two growing years before they are
ready to be planted out. Keeping bushes in cultivation for Additional considerations:
an extended period (e.g. 5 years) so that they are larger
and more resilient is likely to reduce survivorship in the Figure 30. Preparation of heel cutting – lower leaves are • Use only clean sharp secateurs • Keep a record of each parent bush (number of
wild because of increased transplant shock and a prolonged removed in readiness for striking (sterilise blades by wiping with methylated spirits) cuttings taken, GPS grid ref, sex, age, etc); this may
need for aftercare. Conversely planting them young results • Wear thorn-proof gloves be impractical with large populations, instead keep

© Jamie Single - www.superoots.com

in more rapid establishment; two years ex situ is probably • Select branches with strong leading shoots and few tallies of male and female cuttings collected; these
the optimum. berries (avoid sickly shoots) details can be databased at the nursery
• Collect long shoots in the field that can be expertly • Label bags with site name, date and a cross-
If time isn’t a constraint, stock plants can be raised from dissected at the nursery reference to written record
the most vigorous cuttings that in later years will supply • Prevent cuttings from drying out (even on cool
numerous cuttings. However, entire colonies created this days) – keep them out of direct sunlight, in plastic
way may be less adaptable to climate change because bags and use a mist sprayer
they are clones of a few individuals. The effect may be less It’s vital that cuttings are potted up straightaway. If delayed, wrap the cut end of each shoot in damp tissue,
significant when reinforcing populations, depending on the with an elastic band to hold in place. Then store cuttings in plastic bags in a cool dry place – e.g. a cellar. In so
number of clones introduced. doing they should remain viable for several days.
Guidance on taking cuttings is given in Box 8. Under ideal
conditions good quality cuttings will start to root in as Figure 31. Air-Pot grown bush
Planting
little as 6 weeks. Good rooting has been obtained with
Figure 32. The Air-Pot range Whether you are planning on re-establishing a colony, or
heel cuttings in sharp sand (Fig.30). Nonetheless some
expanding an existing one, careful selection of the planting area

© Caledinian tree co Ltd

batches of cuttings inexplicably fail and for this reason we
will pay dividends later. Protected areas and nature reserves
recommend using a specialist nursery.
may provide ideal receptor sites, although undesignated sites
that appear unsuitable may still be worth considering if suitable
Alternatively follow the propagation protocol given
habitat can be restored. Programmes of vegetation clearance and
in Appendix 2. This was produced by the Eden Project
nutrient stripping can in time produce good planting areas.
for subsp. hemisphaerica and its suitability for subsp.
communis remains untested. Due to the ongoing
To maximise the beneficial effects of planting, prepare a detailed
destruction of peatlands, Plantlife strongly advocates the
planting plan. This will later serve as a useful record of the
use of peat-free compost - e.g. Peat Free T2 – produced by
introduction. Adopt a naturalistic planting pattern, mixing sexes
Petersfield Growing Mediums www.peatfreecompost.co.uk
and ages. Reinforcement should be more targeted, addressing
imbalances and discontinuities in the population. Figure 33. Natural juniper scrub at Calstone Down, Wilts
The use of ‘air root pruning’ pots for propagation may
Propagation from seed
Figure 34. Bush cascade, the result of berries tumbling
accelerate growth and increase survivorship after planting down from an upslope female
In the wild, juniper tends to form thickets that are generally
out. The technique produces a dense fibrous root system
lacking other shrub or tree species (Fig. 33). For this reason and its
that prevents roots coiling and plants becoming pot bound. Reliably raising juniper plants from seed is difficult.
susceptibility to competition, the planting of mixed-species stands
There is no need to tease out roots during planting, lowering If results are needed within a predetermined
is inadvisable. However, broadleaf shrubs are frequently browsed in
the risk of damage to root hairs. A well developed root timescale, it is advisable to use a specialist.
preference to juniper so the presence of other shrub species in the
system will also aid establishment in impoverished soils. Pretreatment is necessary to break dormancy but
same compartment may prove not entirely negative.
Air-Pots (Figs. 31 & 32) are made from recycled plastic and even then germination times tend to be sporadic.
are available from The Caledonian Tree Company: www. It can take five years or more before bushes a large
Ideally plant in locations that provide good regeneration habitat –
airpotgarden.com/ enough to be planted out. Information on berry
e.g. the top of steep slopes (Fig. 34), beside pinch points, or along
harvesting, seed processing, storage and sowing
the edges of a well used paths or tracks (unmetalled). Also consider
is given in the Enhancing germination section.
at this stage preventing damage from herbivores – see sections on
Detailed guidance on propagation from seed is
Protection and Grazing exclosures.
available from Forest Research – see Broome (2003)
in Useful References.
Cultivated bushes are ready for planting when they reach at least
20cm in height (depending on their shape) – see Box 9.
30 Reinforcement and reintroduction Breaking new ground for lowland juniper 31
 Box 9. Top tips for planting Protection
Choose guards that will be effective against the biggest
Equipment / materials: work gloves, mattock or spade, trowel, bucket (to collect leaf litter), shrub
and smallest herbivores on site. Preformed shrub-shelters
shelters/guards, stakes, ties (to fix guard to stake), mulch mats & anchoring pegs (optional). with a diameter of 20-30cm and height of 60cm should suit
most circumstances, providing adequate protection against
Great care should be taken when planting Aim to plant out in October-November to allow some
rabbits, rodents and deer. Tree guards tend to be too narrow
out. Bushes will grow less quickly than during root development before winter and in readiness for
resulting in die-back and unnatural bush shapes that may
propagation and their roots need to able to spread the surge of root growth in early spring. Planting in
reduce survivorship once the guards are removed (Fig. 35).
into the surrounding soil. Planting methods will February-March leaves less time for roots to establish,
vary according to whether bushes have been imparting a higher risk of desiccation and failure
The ideal shrub-shelter material is a fine mesh that allows
container or cell grown (e.g. in rootrainers) and over the summer. The problem is more acute on poor
light and air to penetrate but prevents shoots growing
a host of other factors. The following advice is chalky soils and south-facing slopes.
through. If herbicide is to be used to control weed growth,
general; ask your nursery for detailed instruction. Figure 35. Tree guards encourage top-only growth,
take precautions against spray drift. Avoid solid guards and
Adopt a varied spacing pattern that mimics wild leading to a less resilient bush later on.
fake meshes coated in plastic as they create warm humid
To establish readily, transplants need to be young populations. Competition between bushes will be

© Jonathen Crewe
conditions that may be suboptimal for juniper.
with a high proportion of roots to shoots. Well before reduced by planting at least two metres apart which
planting out, ‘harden off’ the young bushes to may be critical when young bushes are of varied
Climatic Plus shelters (Figs. 36 & 37) have a proven track
acclimatize them to growing outdoors. Over several height/vigour (e.g. when grown from seed). Where
record for juniper and are available from Trees Please
weeks, move them from the greenhouse to a sheltered interstitial grassland exists – e.g. glades – allow
(Northumberland): http://www.treesplease.co.uk/
location outside for increasingly longer periods. sufficient access for grazing stock.
These guards are UV-biodegradable but are stated to last
A step-by-step guide to planting a container-grown bush: more than 10 years.
1. Choose a calm cloudy day Fitting a mulch mat /sheet will reduce root desiccation (the
2. Ensure bush is well watered before planting main reason for transplant failure) and reduce competition
3. Dig a square-sided hole slightly wider and deeper than the pot from weeds (Fig. 37). Without mats, it may be necessary to
4. Mix organic matter such as leaf litter, or chopped turves, with the soil manually weed shelters although this can be a difficult and
5. Keeping the bush in its container, adjust the planting depth so that the top of root ball will be just covered time consuming task.
with soil once planted (exposed compost will increase water loss)
6. Only expose the root ball at the moment of planting, disturbing the roots as little as possible Shelters should be double-staked and fitted tight to
Figure 36. Climatic Plus shrub shelter installed with two
7. Badly pot-bound plants have stiff spiralled roots; return them to the nursery for replacement stakes and a mulch mat.
the ground to exclude voles. After 5 years, shelters and
8. In less severe cases, gently tease out coiled roots so that they point away from root ball when planting

© Jonathen Crewe
mulch-mats should generally be removed and if necessary
9. Keep the bush vertical whilst backfilling the mixture replaced with another means of protection.
10. Firm backfill around root ball, gently heel in and water thoroughly
11. Fit a mulch mat, or place upturned sods around the base of plant but ensuring the stem itself is kept As well as presenting a barrier to herbivores, guards
entirely clear stifle the wind. Buffeting of transplants can prevent root
12. Take care not to skewer the root ball when staking the guard establishment. This is a particular problem on exposed sites
with thin rocky soils where bushes may be poorly anchored
after planting. To prevent guards being blown over, ensure
stakes are aligned with the prevailing wind.

A good bespoke alternative is a post and rail triangle

or square with toughened plastic/wire netting that can
be dug into the ground. Chicken wire should be avoided
because shoots grow through and become trapped (Fig. 38). Figure 37. View of mulch mat inside shelter
Although post and rail constructions are more sturdy and Figure 38. Chicken wire provides some protection but is
stock-proof, considerable time and resources are needed, difficult to remove in later years as shoots become entangled.
making them less practical for large planting schemes.

© Jonathen Crewe
On sites where guards are likely to attract complaints or
vandalism, mounds of encircling spiny twigs offer a less
conspicuous alternative (Box 5).

On stock-grazed land, a sturdy fenced exclosure or electric

fence is best to eliminate the possibility of trampling and
rubbing. When multiple threats exist, combinations of
rabbit netting and vole guards have been shown to be highly
effective (see Grazing exclosures).

32 Reinforcement and reintroduction Breaking new ground for lowland juniper 33

Monitoring and aftercare
Bushes should be checked regularly during the first
year after planting, and annually thereafter for at
least five years.

Aftercare has three key components:

1. Removal of competitive vegetation
2. Maintenance of grazing protection
3. Prevention of desiccation

The control of weeds surrounding planted bushes has

been shown to be a major factor determining growth
rates and survival. Mulch mats will give transplants
a head start but may be considered unsightly. Weed
in the spring, clearing a 50cm swathe around the
stem of each bush. Most sites will require annual
weeding but on fertile soils more frequent weeding
is advisable. Where guards are fitted, manually
remove detritus and rank vegetation from inside.

The careful application of an appropriate herbicide

may offer an efficient alternative particularly for larger
planting schemes but should only be used where
there is negligible chance of damaging juniper.

Check bushes are still firm in the ground (tread

them in as necessary), re-stake loose shrub-
shelters and replace torn mulch mats. Check the
integrity of exclosure fences; grazed or browsed
vegetation inside would indicate a breach. Documenting
Although juniper is well adapted to dry conditions, Recording the numbers, sex and
emergency watering during droughts, especially exact locations of planted bushes
in the first year after planting, is likely to greatly is important. When evaluating the
increase survival rates. Spring-planted bushes national status of juniper in the
are particularly vulnerable to desiccation. wild, or the conservation value of a
particular site, we need to know to
Depending on their size at planting, subsequent what degree populations are natural
root development and situation, bushes can take as opposed to introduced or enhanced.
many growing seasons to become strong enough Please ensure records are passed to
to survive in the wild unaided. Before removing your Local Record Centre, Vice County
guards or dismantling exclosures, test the browsing Recorder or Plantlife.
impact by exposing one or two bushes.

34 Reinforcement and reintroduction Breaking new ground for lowland juniper 35

Appendix 1 Appendix 2
Propagation protocol for
Step-by-step guide to seed processing Juniperus communis subsp. hemisphaerica
Equipment / materials: food processor, several bowls, spoon or egg-whisk,
Juniperus communis subsp. hemisphaerica is a dwarf Potting Media
kitchen sieve, tea strainer, paper towels. You will also need access to cold evergreen dioecious shrub. For finished 5L pot plant. 80% Vapogrow seed and modular compost, 10% Perlite
running water and, if storing seed afterwards, use of a domestic fridge. standard and 10% sterilised Loam.
Propagules
1. Sort through berries one container at Fertilization
a time, discarding any green, brown or Stage 1 (unrooted cuttings) No fertilisation required in stage 1. In stages 1-4 use
wrinkled ones. Cutting material taken from Gew Graze in early February 1 gram per litre of Osmocote, 12-14 months 15-9-11
and/or October from one year old semi-ripewood tip +2Mgo + TE in growing media. Supplement with a liquid
cuttings or semi ripewood cuttings with ripe heel, feed with half strength Peters Excel, 15:5:15 Mgo + TE
2. Mash blue-black berries to release the seed.
6-9cm in length resulted in over 80% rooting success. 0.3g/l on a fortnightly basis.
Small numbers of berries can be processed Cuttings taken at the end of February had a higher
by rubbing off the pulp by hand using a rooting success. The bottom leaves of cuttings should Temperature
fine-gauze sieve but this can be messy be carefully removed with a sharp propagation knife Juniper will survive temperatures of -5°C. At
and time consuming. Instead, use a food before the base of cutting is dipped for five seconds in temperatures below -2°C ensure that plants are
processor or electric mincer with a medium Synergol 10000ppm IBA. Diluted 1:5.6 giving a 1500ppm protected by fleece.
mincing screen (5mm holes) – anything IBA and placed into modules compost mixture 25%
finer will destroy the seed. to 75% grit (higher percentage of grit is a necessity Light
for high percentage rooting as Juniper dislikes being Ensure cuttings and plants are shaded and away from
waterlogged.) Cuttings were watered in and placed on a direct sunlight. Junipers grow well under glass and
3 Put the result into a large bowl and fill with
gravel based mist bed in a Venlo glasshouse with bottom when large enough can be moved outside with up to 20
cold water. Stir the mixture with a whisk or heat of 20°C, on electronic leaf activated keeping the percent shading in the UK.
spoon to release trapped air, then allow to leaves just moist. It is crucial at all times not to let
settle. This can be done in stages if large the cuttings dry out as this will significantly reduce Irrigation
numbers of berries are being processed. percentage rooting success. Do not propagate in direct It is crucial at all times not to let the plants dry out as
sunlight as can cause scorching. Growing temperatures: this will significantly reduce percentage survival success.
4. Seed that floats is empty and should be Nights: 8-10 ° C Days: Max 16°C. Cuttings taken in The media requires to be free draining as the roots do not
skimmed off and discarded (a tea strainer is Feb take up to three months to root. Cuttings taken in like to be waterlogged.
ideal for this purpose). Conversely seed that October take up to six months to root.
Spacing
has sunk to the bottom is mainly viable,
Stage 2 Throughout all stages space so that the plants do not
and can be sieved off afterwards. Once rooted, wean off cuttings for two weeks by reducing overlap.
mist bursts followed by removal from mist bed and
5. Flush the good seed under cold running pot on into 9 cm square pots (during potting on ensure Crop Schedule (Last week in February)
water until clean. that root disturbance is kept to a minimum.) Place on
mypexed floor in glasshouse with growing temperatures Rooting stage: Up to 90 days (3 months)
6. Allow to drain before tipping onto absorbent of minimum 8-10 °C and maximum 20°C. Weaning: Up to 14 days (2 weeks)
kitchen towelling. Stage 2- Stage 3: Up to 364 days (12 months)
Stage 3 Stage 3 – Stage 4: Up to 364 days (12 months)
7. Leave at room temperature until dry Pot on 9 cm to 2L pot (during potting on ensure that Stage 4 – Transplantation: Up to 90 days (5 months)
root disturbance is kept to a minimum.). Remain in
(do not oven-dry).
glasshouse on floor in Venlo glasshouse with growing Total Time: Up to 980 days (33 months)
temperatures of minimum 8-10 °C and maximum 20°C.
8. Estimate the number of seed by volume. When outside temperatures reach above 5°C place Crop Schedule (October)
One level teaspoon (5ml) = about 200 outside on hard standing. Ensure the plants remain
seeds. Alternatively, 100 seeds weighs outside and fleece if temperatures go below -2°C. Rooting stage: Up to 180 days (6 months)
approximately 1gram. Weaning: Up to 14 days (2 weeks)
Stage 4 Stage 2- Stage 3: Up to 240 days (8 months)
9. Keep seed in a household fridge. Pot on 2L into 5L pots (during potting on ensure that root Stage 3 – Stage 4: Up to 364 days (12 months)
disturbance is kept to a minimum.). Place outside on Stage 4 – Transplantation: Up to 90 days (5 months)
hard standing with shade. Keep the plants outside above
-2°C and fleece if temperatures go below this. Total Time: Up to 980 days (33 months)

Preparation for Transplantation Pests and diseases

Slightly reduce irrigation of plants over a five month Keep vigilant at all times with regards to monitoring for
period to prepare for planting out. Ensure that the plants Pests, Diseases and Viruses. Plants have been attacked
are checked with regards to pests, diseases and viruses by Totrix moth.
and that these are treated before the transplantation
process occurs.
36 Appendices Breaking new ground for lowland juniper 37
Useful references Key contacts
Agate, E. (Ed) (2000). Tree Planting & Aftercare – a practical handbook. BTCV, ISBN 0-946752-25-7. Buckinghamshire County Council National Trust – SW England
Julia Carey Simon Ford
Broome, A. (2003). Growing Juniper: Propagation and Establishment Practices. Forest Research Countryside Officer Wildlife and Countryside Advisor
Information Note 050, ISBN 0-85538-603-7, available as a free download from: www.forestry.gov.uk jcarey@buckscc.gov.uk simon.ford@nationaltrust.org.uk

Crofts, A. & Jefferson, R.G. (1999). The Lowland Grassland Management Handbook (2nd edition). Eden Project Natural England
English Nature/The Wildlife Trusts, ISBN 1-85716-443-1, available as a free download from: Dr Alistair Griffiths Graham Steven
http://naturalengland.etraderstores.com/NaturalEnglandShop/Grassland Curator (Horticultural Science) Senior Reserves Manager
AGriffiths@EdenProject.com Graham.Steven@naturalengland.org.uk
Day, J., Symes, N.C., Robertson, P.A. & Bacon, J. (Ed) (2003). The Scrub Management Handbook.
FACT, ISBN 1-85716-745-7, available as a free download from: Forestry Commission Research Agency Plantlife
http://naturalengland.etraderstores.com/NaturalEnglandShop/IN124 Dr Shelagh McCartan Tim Wilkins
Seed Scientist Species Recovery Co-ordinator
Herbert, R. (1999). Using Local Stock for Planting Native Trees and Shrubs. Forest Research Practice shelagh.a.mccartan@forestry.gsi.gov.uk Tim.Wilkins@Plantlife.org.uk
Note 008, ISBN 0-85538-503-0, available as a free download from: www.forestry.gov.uk.

JNCC (2003). A Policy for Conservation Translocations of Species in

Britain. Available as a free download from: http://www.jncc.gov.uk/page-2920

McBride, A. (2005). Managing uplands for Juniper. Plantlife Back from the Brink Management
Series, ISBN 1-904749-05-4. Available as a free download from:
http://www.plantlife.org.uk/uploads/documents/Management-Managing-uplands-for-juniper.pdf

Malcolm, D.C. (2000). Genetic variation and conservation of British native trees and shrubs: current
knowledge and policy implications. Forestry Commission Research Report, ISBN 0-85538-412-3.

Thomas, P. A., El-Barghathi, M., & Polwart, A. (2007). Biological Flora of the British Isles: Juniperus
communis L. Journal of Ecology, 95(6), 1404-1440, available as a free download from:
http://onlinelibrary.wiley.com/ Supported by:
Ward, L.K. (2004). Juniperus communis L. Plantlife Species Dossier. Available as a free download
from: http://www.plantlife.org.uk/uploads/documents/Juniperus_communis_Dossier_complete.pdf

Ward, L.K. & King, M. (2006). Decline of juniper in Sussex. Quarterly Journal of Forestry,
100, 263 –272.

Ward, L. K. (2010). Variation in ripening years of seed cones of Juniperus communis L., Watsonia,
28, 11-19.

Wilson, S.M. & Samuel, C.J.A. (2002). Genetic conservation of native trees. Forest Research Annual In partnership with:
Report, pp 57-62, available as a free download from: www.forestry.gov.uk
design - evansbleep.co.uk

38 Useful references & Key contacts Breaking new ground for lowland juniper 39
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