OREGON STATE UNIVERSIT Y EXTENSION SERVICE

WILLAMETTE VALLEY • SOUTHERN OREGON

CENTRAL OREGON • EASTERN OREGON

GROWING BLACKBERRIES
IN YOUR HOME GARDEN
Photo: Betsy Hartley, © Oregon State University

Also available: B. Strik, E. Dixon, A.J. Detweiler and N. Sanchez

D
Growing Berries on the
Oregon Coast: Raspberries and
ark, delicious blackberries have been gaining in popularity. Many Oregonians
Blackberries, EM 9180, https:// could pick their fill from vines growing along roads and trails. But those who
catalog.extension.oregonstate. grow blackberries in the home garden can enjoy a choice of cultivars, or
edu/em9180 varieties, with superior fruit. What’s more, home gardeners can pick fruit from early
Growing Berries on the summer all the way to the first frost.
Oregon Coast: An Overview, Blackberries are in the caneberry group, which also includes raspberries and
EM 9177, https://catalog.
raspberry-blackberry hybrids. Caneberry plants produce fruit on hard, woody stems
extension.oregonstate.edu/
em9177 called canes.
Raspberries and blackberries both produce a fruit made up of many individual
sections, or drupelets (Figure 1, page 2). Each drupelet encloses a seed. When you
pick a raspberry, the fruit comes off the receptacle — the white central core that
stays on the plant — and the berry is hollow inside. In blackberries, the receptacle
stays attached to the fruit when you pick it. Blackberries are not hollow (Figure 1).
Raspberry-blackberry hybrids such as ‘Boysen’ and ‘Logan’, also known as
“boysenberry” and “loganberry,” are classified as blackberries.

Bernadine C. Strik, Extension berry crops specialist and professor of horticulture; Emily Dixon, instructor, horticulture; Amy Jo
Detweiler, community horticulture, Crook, Deschutes and Jefferson counties, and professor; Nicole Sanchez, Extension horticulture
field faculty, Klamath, Harney and Lake counties, assistant professor (practice); all of Oregon State University.

EC 1303
Revised September 2020
 Receptacle
Receptacle
Receptacle
Drupelet

Drupelet

Photos: Bernadine Strik, © Oregon State University

Figure 1A. The receptacle, or Figure 1B. The receptacle of a Figure 1C. In blackberry, the receptacle is part of the fruit.
plug, stays on the plant when black raspberry also stays on the
you pick a raspberry. plant when you pick it.

You can find several blackberry species in the wild in

Oregon. Only one, the western dewberry (Rubus ursinus)
is native (Figure 2). Plants have a trailing growth habit
with purplish-colored stems. There are separate male
and female plants; females produce oblong fruit with
small seeds and a wonderful aromatic flavor.
Two other species introduced from Europe in the late
1800s have become endemic and can be found in most
areas of Oregon. The first species, Rubus armeniacus,
has been given a cultivar name, ‘Himalaya’ (Figures 3A,
Photo: Bernadine Strik, © Oregon State University
3B). This extremely vigorous blackberry spreads easily
Figure 2. Western dewberry (Rubus ursinus), a native plant.
through seeds after passing through birds, and it has
become a noxious weed. Its growth habit is similar to
semierect types (see page 3). The other introduced
species, Rubus laciniatus (Figure 4, page 3), with the
cultivar name ‘Evergreen’, was grown commercially for
many years before it became endemic. This trailing
blackberry has lacy leaves and produces small, sweet
fruit in midsummer; cultivars are no longer available for
home gardeners. The cultivars listed in Table 1 (page 5)
have excellent fruit quality.
Blackberries have a unique growth habit. The plants
have a perennial root system and crown, or plant
base, but the canes are biennial, dying after fruiting. Photo: Bernadine Strik, © Oregon State University
Blackberry plants have a lifespan of 15 to more than 40 Figure 3A. Introduced, weedy ‘Himalaya’ blackberry (Rubus
years, depending on the presence of pests or adverse armeniacus) at bloom in western Oregon.
environmental conditions.

Blackberry types
BLACKBERRY CANES
The two names for a blackberry cane describe whether the
cane is in its first or second year of growth:
Primocane: First year of growth. Most cultivars produce
no fruit on these canes.
Floricane:Second year of growth. These canes produce
Photo: Bernadine Strik, © Oregon State Universit
flowers and fruit and then die.
Figure 3B. ‘Himalaya’ blackberry (Rubus armeniacus) fruiting.

2
 after fruiting. After the planting year, blackberry
plants have both types of canes — primocanes and
floricanes — at the same time (Figure 5).
• Primocane-fruiting (also called fall-fruiting or
everbearing) blackberries have a similar cane
development and lifecycle, except the tips of the
primocanes (Figure 6A) or primocane branches
(Figure 6B) flower and fruit in the late summer
or fall of their first year of growth, depending on
summer pruning (see “Pruning and training,” page
Photo: Bernadine Strik, © Oregon State University
14). The portion of the primocane that fruited dies
Figure 4. Introduced, weedy ‘Evergreen’ blackberry (Rubus back in late fall or winter. Then the remaining cane
laciniatus) in western Oregon. base will overwinter and fruit as a floricane in its
second year. Floricanes die after fruiting. Everbearing
blackberry plants can be pruned to produce one
crop (primocane only) or two crops (early summer
on floricanes and late-summer and fall on new
Floricanes and primocanes).
fruiting laterals

tion
sec
e ring
Flow

Primocanes Photo: E.J. Albaugh, © Oregon State University

Figure 6A. Bernadine Strik displays an unpruned primocane
flowering at the tip in early September. This specimen is an
everbearing erect blackberry.

Photo: Bernadine Strik, © Oregon State University

Figure 5. A trailing ‘Marion’ blackberry in early summer shows new
primocane growth. Some fruit is starting to ripen on the fruiting
laterals of the floricanes.

Fruiting habits
• Floricane-fruiting (also called summer-bearing)
blackberries produce vegetative canes, called
primocanes, in the spring. Primocanes grow from
buds on the crown and the roots, depending on the Fruiting on one of
type (see below) (Figure 5). These primocanes grow several branches
throughout their first year and then go dormant in
the fall. They overwinter and then produce flowers Photo: E.J. Albaugh, © Oregon State University

and fruit in their second year, at which point the Figure 6B. Bernadine Strik displays the fruiting tips of branches
canes are called floricanes. The floricanes die on a pruned primocane of an everbearing erect blackberry in
late September.

3
 Early growth
on floricanes

Bloom on
floricanes

Primocanes growing
from crown
Primocanes growing
from crown

Primocane growing
from a bud on root

Photo: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figure 7. A summer-bearing erect blackberry in spring shows Figure 8. A summer-bearing semierect blackberry in spring shows
early growth of fruiting laterals on the floricanes and primocanes bloom on floricanes and primocanes emerging from the crown.
emerging from crowns and roots. The primocanes will remain upright.

Growth type • Erect blackberry cultivars include summer-

There are three main blackberry types suited to the bearing (such as ‘Navaho’) and primocane-fruiting
home garden, depending on your region. They are or everbearing (such as ‘Prime-Ark Freedom’)
differentiated by their cane growth habit — trailing, (see “Blackberry cultivars,” page 6). This type
erect and semierect. produces stiff, erect canes that need pruning in
summer (tipping primocanes) as well as winter. New
• Trailing blackberry cultivars produce primocanes primocanes are produced each year from the crown
that are not self-supporting. They trail along the and buds on the roots (Figure 7), so these plants can
ground unless they are trellised (Figure 5, page spread. This type of blackberry fruits in midseason
3). Primocanes are produced only from buds on on the floricanes (early July through August in the
the crown and may grow more than 15 feet long, Willamette Valley). Everbearing cultivars fruit on the
depending on the site and cultivar. Cultivars primocanes from early September through fall frost.
in this group include ‘Marion’ (also known as Fruit have a milder aroma and flavor and larger seeds
“marionberry”), ‘Hall’s Beauty’, ‘Columbia Star’, than the trailing types; berries are glossy and firm.
and the raspberry-blackberry hybrids ‘Boysen’ This type of blackberry, whether summer-bearing or
(“boysenberry”) and ‘Logan’ (“loganberry”) everbearing, is the most winter cold hardy and can be
(see “Blackberry cultivars,” page 6). This type of grown in all regions of Oregon.
blackberry has the earliest fruiting season (late June
through early August in the Willamette Valley) and • Semierect blackberry cultivars produce vigorous,
produces fruit with small seeds and excellent flavor thick and arching primocanes from the crown of
and aroma. These cultivars are good for eating fresh the plant (Figure 8). Like erect types, they benefit
and for freezing or jams; seeds do not need to be from summer pruning, to tip primocanes, and from
removed prior to making pies or jam. This type is winter pruning. All cultivars are summer-bearing
the least winter cold hardy and heat tolerant (see (‘Triple Crown’, for example) and are the latest
“Common problems,” page 19) and is best adapted summer-bearing cultivars, fruiting from early August
to the Willamette Valley and southwestern Oregon. to September or October in the Willamette Valley.
It can be grown in some other regions with methods This type may be grown in most regions of Oregon,
to improve cold hardiness (see “Pruning and training,” depending on hardiness zone and cultivar (see
page 14, and “Common problems,” page 19). “Blackberry cultivars,” page 6).

4
Table 1. Blackberry cultivars

Trailing Summer-bearing; one crop per season on floricane Erect summer-bearing One crop per season on floricane
Thornless;
‘Navaho’
excellent
Zone 5 or 6–9
flavor
‘Marion’
‘Ouachita’ Thornless;
Zones 6–9 Zone 5 or 6–9 good flavor
Thorny, soft, excellent flavor
‘Caddo’ Thornless;
Zones 5–9 good flavor
‘Marion’
‘Kiowa ’ Thornless;
‘Navaho’ Zones 6–9 good flavor

Erect everbearing May produce two crops per season –

first on floricane, second on primocane. Most cold-hardy.
‘Columbia Star’
Zone 5 or 6–9
‘Prime-Ark Freedom’
Thornless; very good flavor
Zones 5–9
Thornless; fair to good flavor
‘Columbia Star’

‘Black Gem’
Zones 5–8
Thornless
‘Hall’s Beauty’ ‘Prime-Ark® Freedom’
Zones 6–9
Thornless; maroon-colored Semierect Summer-bearing; one crop per season on floricane
fruit; good flavor
‘Triple Crown’
‘Hall’s Beauty’ Zones 5 or 6–9
Thornless; excellent flavor

‘Galaxy’
‘Columbia Giant’ Zones 5–9
Zones 6–9 Thornless; good flavor
‘Triple Crown’
Thornless; mild flavor

‘Columbia Giant’
‘Eclipse’
Zones 5–9
‘Boysen’
Thornless; good flavor
Zones 6–9
Raspberry-blackberry hybrid;
maroon fruit with excellent ‘Eclipse’
flavor; thornless clones may
revert to thorny canes over
time.
‘Boysen’
‘Twilight’
Zones 5–9
‘Logan’ Thornless; excellent flavor
Zones 6–9
Raspberry-blackberry hybrid;
some thornless clones ‘Twilight’
available; dark red fruit; plants ‘Eclipse’ photo by Chad Finn; all others by Bernadine Strik, © Oregon State University
susceptible to cane disease
‘Logan’

5
Blackberry cultivars various nurseries. Make note of the cold hardiness
zone, because this may limit production in your region.
It is important to choose a cultivar adapted to your Whichever types and cultivars you choose, buy
region. Various types of blackberry differ in fruiting only certified, disease-free plants from a reputable
season and cultural requirements. Even cultivars within nursery. It can be tempting to start your new planting
the same type (trailing, erect or semierect) differ in by digging up “suckers” — primocanes that developed
fruit quality and flavor, appearance, tolerance to pests, from buds on the roots — from your old patch or that
cold hardiness, and plant longevity. of a neighbor. That route is easy and free. But it could
Winter cold-hardy cultivars adapted to the colder also introduce pest-infested soil and virus-infected
regions of Oregon (such as zones 5 to 7), may not plants to your new planting. Also, many cultivars
grow normally in regions of the Willamette Valley are patented and may only legally be propagated by
(zone 8) where winters are warmer and plants licensed nurseries. Many of the cultivars in Table 1 (and
receive less winter chill. Also, cultivars adapted to more) are available through local retail and mail-order
the Willamette Valley (most of which is zone 8) may nurseries. Plants often sell out quickly, so order well in
lack sufficient cold hardiness for central, eastern and advance of spring planting.
southeastern Oregon (see “Common problems,” page Because blackberry cultivars do not need cross-
19). If you choose a summer-bearing cultivar or want pollination to produce fruit, you only need to choose
to grow an everbearing cultivar for a double crop, one cultivar. However, growing more than one type or
then the cultivar must have sufficient cold hardiness cultivar will allow you to compare them, have sufficient
on the overwintering cane to get a floricane crop; fruit for freezing or jam, and to have fresh fruit for an
this overwintering primocane is exposed to cold extended period.
temperatures and potentially desiccating winds.
In contrast, an everbearing cultivar may be grown
for a primocane crop only (single crop) in any Site selection
production region, because no overwintering cane Blackberry plantings are productive from 15 to
is needed for this production method — only the more than 40 years, depending on type, soil and
crown overwinters in this system (see “Pruning and pest pressure. Carefully select a site for optimal
training,” page 14). planting life. Ideal environmental conditions for
The raspberry-blackberry hybrids (‘Boysen’, ‘Logan’ blackberries are full sun exposure and fertile,
and ‘Tayberry’) are trailing blackberries with less cold well-drained, sandy loam or clay loam soils with
hardiness than either erect or semierect cultivars. If moderate water-holding capacity. In Central
you live in an area that has borderline cold hardiness Oregon, amend native soil with compost to increase
for any trailing cultivar (see below), or your yard is its water-holding capacity. Blackberry plants are
more exposed to cold winds in winter (such as at tolerant of wet, heavy soils and usually don’t need
higher elevation or exposed sites in the Willamette to be planted in raised beds. While plants can
Valley or southwestern Oregon), then choose a tolerate partial shade, yield and fruit quality may be
warmer or more protected site for consistent fruit lower. If possible, avoid spots in your yard exposed
production. Depending on your location or region, to high winds, which may increase risk of winter
consider training methods that reduce the risk of cold injury to primocanes in susceptible cultivars
winter cold injury, and use other means of protecting (see “Common problems,” page 19).
these cultivars as needed (see “Common problems,” It is important to eliminate perennial weeds before
page 19). planting because they are hard to control after
Table 1 (page 5) lists cultivars noted for good planting. Don’t let annual or perennial weeds go to
flavor and pest resistance by type. The table lists a seed, and ensure that any amendments you apply,
range in cold hardiness zones to help you determine such as composted yard debris or manures, are free of
regional adaptation if you are growing in an area with weed seeds.
a borderline USDA Cold Hardiness Zone (https://
planthardiness.ars.usda.gov/PHZMWeb/#). Be aware
that cold hardiness zones vary within any one region. Soil nutrient testing and modification
You may be in zone 5 because your home is at a higher You can grow blackberries in raised beds or
elevation, while the majority of the region is in zone 6. containers with a good potting mix (see “Container
See Blackberry Cultivars for Oregon, EC 1617, https:// plantings,” page 9). But if you are going to plant
catalog.extension.oregonstate.edu/ec1617, or Selecting blackberries in your garden soil, it is a good idea to
Berry Crop Varieties for Central Oregon, EC 1621, take a soil sample and have it tested prior to planting.
https://catalog.extension.oregonstate.edu/ec1621. You Collect soil samples up to a year or more in advance.
can find descriptions of newer cultivars online through This will provide adequate time to amend the soil, if

6
necessary. Take soil samples from the top 12 to 18 buffer test is probably not necessary. Ideally, test the
inches of soil where the roots will grow. soil a year before you plant to give yourself enough
Blackberries require a soil pH of 5.6–6.5. If your soil time to modify the soil pH, if required. If the soil pH
test indicates that your soil pH is too low (too acidic) or is too high (above 6.5), add elemental sulfur to acidify
too high (too basic) for blackberry production, you can the soil; the rate depends on soil type and the current
amend the soil to improve the pH. A typical soil analysis pH of the soil. In sandy soils, apply approximately 1
will also include phosphorus (P), potassium (K), calcium to 3 pounds per 100 square feet; in clayey soils, apply
(Ca), magnesium (Mg) and sodium (Na). In addition, it approximately 5 to 6 pounds per 100 square feet. For
is beneficial to test for organic matter and boron (B), more information, see Acidifying Soil for Blueberries and
especially in the Willamette Valley, where B deficiency Ornamental Plants in the Yard and Garden, EC 1560,
is common in blackberries. Nitrogen (N) levels in soil https://catalog.extension.oregonstate.edu/ec1560,
are not useful because N is not added prior to planting. and Acidifying Soil in Landscapes and Gardens East
Instead, supply N with fertilizer after planting. The table of the Cascades, EC 1585, https://catalog.extension.
below shows recommended nutrient ranges in soil for oregonstate.edu/ec1585.
blackberry. In general, if your soil pH is too low (below 5.6)
For more information, see A Guide to Collecting for blackberry production, incorporate finely ground
Soil Samples for Farms and Gardens, EC 628, https:// limestone at a rate of approximately 5–10 pounds per
catalog.extension.oregonstate.edu/ec628; Analytical 100 square feet. You can also use high-pH composts
Laboratories Serving Oregon, EM 8677, https:// to add organic matter and increase soil pH. However,
catalog.extension.oregonstate.edu/em8677; and Soil avoid composts with a high salt content (electrical
Test Interpretation Guide, EC 1478, https://catalog. conductivity or EC), such as fresh animal manures.
extension.oregonstate.edu/ec1478. Incorporate amendments into the soil about a year
prior to planting, as it takes time for the soil pH to
Table 2. Recommended soil nutrient range adjust after the addition of lime. See Applying Lime to
for blackberries Raise Soil pH for Crop Production (Western Oregon),
EM 9057, https://catalog.extension.oregonstate.edu/
Soil nutrient Deficient at less than (ppm) em9057, and Eastern Oregon Liming Guide, EM 9060,
https://catalog.extension.oregonstate.edu/em9060.
Phosphorus (P)
Bray 1 testing
20–40
Organic matter
method Blackberry plants tend to grow better with a soil
Olsen testing organic matter higher than 3%. You can increase soil
10
method organic matter content by amending it with fine, aged
Potassium (K) 150–350 woodchips or sawdust, bark, well-composted manures
or plant-based composts. Manure or composts are
Calcium (Ca) 1,000 the best options for amending native soil in Central
Magnesium (Mg) 120 Oregon. It is important that whatever material you
Boron (B) 0.5–1.0 apply is free of pest insects and weed seeds. Apply
organic matter at a rate of 1–2 inches deep for each
area planted. All of these organic materials differ in
Soil that is not ideal for blackberries (soil with the nutrient content, pH, salt content (EC), and carbon
wrong pH, poor rooting depth or low organic matter) to nitrogen ratio (C:N), which affect the rate of
can usually be improved by increasing organic matter decomposition. For more information on use of organic
content, building raised beds, modifying soil pH to the matter in crop production, see Improving Garden
ideal range through amendment with lime or sulfur, Soils with Organic Matter, EC 1561, https://catalog.
and modifying soil nutrient levels, if needed. extension.oregonstate.edu/ec1561.
Incorporate the organic material into the soil by
Soil pH digging or tilling. Mixing the amendment in well
In the Willamette Valley and some regions of ensures uniformity of soil properties. If you apply
southern Oregon, a test known as the Shoemaker- large amounts of fresh organic material with a high
McLean-Pratt, or SMP, buffer test is helpful for C:N, such as sawdust, aid decomposition by applying
determining how much lime to apply if the soil pH is approximately 3 ounces of N per 100 square feet
below the ideal range for blackberries. You can ask (see calculation below). In areas with little summer
for this to be included on your soil nutrient analysis. rain, irrigate the intended planting area to ensure
In central, eastern and southeastern Oregon, soils amendments such as lime or sulfur and organic
tend to be neutral to more alkaline, so this additional materials react well with the soil.

7
Planting
Blackberry plants are sold as either bare-root plants
(a short cane section with roots attached, Figure 9) or
as potted plants (Figure
10). Plant blackberries
as early as you can
work the soil in spring.
If they can’t be planted
immediately, heel in bare
root plants by covering
the roots with moist soil
or sawdust.
When planting, dig
a shallow hole large
enough to accommodate
Photo: Bernadine Strik, the roots. For bare-root
© Oregon State University Photo: Neil Bell, © Oregon State University
plants, planting methods Figure 10. Semierect blackberry nursery plants.
Figure 9. Blackberry bare-root
depend on the type of
nursery plants.
blackberry:
• For trailing and semierect cultivars, make a Remove primocanes that
planting hole large enough to accommodate the root fall outside the 12-inch
ball width and depth (when holding the cane section width of the hedgerow
in your hand). Fill the planting hole with soil while
holding the cane section. Set the plant so that the
roots attached to the cane fall from 1 to 2 inches
below the soil surface.
• For erect summer-bearing or everbearing
cultivars, make the planting hole more shallow so
that the roots are spread out more. Cover the roots
with soil so that the highest point of attachment of
roots to cane is 1 to 2 inches below the soil.
For potted plants of any type, dig a hole large enough
to accommodate the size of the root ball. Remove the
pot, run your gloved hand to rough up the roots on
the exterior of the root ball, and set the plant so that Photo: Bernadine Strik, © Oregon State University
the pot’s container mix is level with the soil. Fill the Figure 11. Everbearing erect blackberry planting in spring
planting hole with soil and firm the soil to remove air showing primocane growth in a single crop pruning system.
pockets. Maintain row width to about 12 inches by pruning out any canes
Water thoroughly after planting and cut the canes outside the row during the growing season.
of newly planted bare-root plants to 6 inches, if they
are longer. Water young plants frequently, regardless of are most commonly grown in a hedgerow (Figure
whether they came in a pot or as bare-root plants, to 11). A hedgerow refers to maintaining the row to
ensure the roots do not dry out. about 12 inches wide by removing any primocanes
that emerge outside this width by pruning, hoeing or
rototilling. Over time, individual plants become less
Plant spacing evident in a hedgerow planting. Space summer-bearing
The plants of trailing and semierect blackberry and everbearing plants 2.5 to 3 feet apart in the row,
cultivars should be grown as individuals because with 10 feet between rows. Keep any primocanes that
they do not produce new primocanes from the roots. emerge in the row area between plants. Remove any
Space trailing plants 3 to 5 feet apart in the row and primocanes that emerge outside this in-row area as
semierect plants about 5 feet apart. Rows should be 10 they start to grow, as described above. If you allow
feet (trailing types) to 12 feet (semierect types) apart. wider hedgerows, management tasks such as weeding,
Since erect blackberry cultivars produce primocanes pruning and harvest become more difficult and disease
from buds on their roots as well as the crown, plants potential increases due to the dense canopy.

8
Container plantings
When soil in the garden is not well suited for
blackberry production (even after you make all possible
amendments) or space in the yard is limited, you can
grow blackberry plants in containers on a deck or in
constructed raised beds (Figures 12 and 34). Choose a
site that has good sun exposure.
The best blackberries for container production
are everbearing, primocane-fruiting erect cultivars
pruned to produce two crops per season (see
“Pruning and training”). However, trailing cultivars
may also be grown in containers or raised beds
using similar methods described for field plantings.
Semierect blackberry cultivars are generally too
vigorous to grow easily in containers, but may be
grown in larger raised beds.
Since blackberry plants are relatively deep rooted,
they require a deep pot or raised bed (a minimum of
2 feet deep). A 20- to 30-gallon container works well,
but careful pruning is needed to ensure the plant
doesn’t get too large for the container. In a raised bed,
blackberry plants should be established using the plant Photo: Bernadine Strik, © Oregon State University
spacings recommended below. For more information Figure 13. Trailing blackberry being grown with a weed mat for
on building raised beds, see Raised Bed Gardening, FS weed control in the Willamette Valley.
270, https://catalog.extension.oregonstate.edu/FS270.
The potting mix and the container must drain Mulching
well. Make sure that water will drain into the soil
below a constructed raised bed. A recommended soil A mulch can help control annual weeds, conserve
mixture is one part perlite or pumice, one part finely soil moisture, and, depending on the type of mulch,
ground bark, and two parts garden or potting soil; provide a source of nutrients. Be careful to not bury the
yard centers may sell a similar mix in bulk. If desired, crown with an organic mulch, as this can promote rot.
mix slow-release or sulfur-coated fertilizer into the Deep straw should not be used as a mulch during the
potting mix at a rate of 8 cups per cubic yard of growing season because it can lead to increased vole
potting mix. or rodent activity, which can damage the plants. If you
are growing in an area where the soil can freeze and
Follow the planting, fertilizing and pruning
thaw during winter, leading to heaving, apply a mulch
recommendations described here.
around the crown to help protect plants from winter
cold injury.
Trailing and semierect blackberry plants may be
grown with a weed mat mulch (a porous polypropylene
groundcover) to aid in weed control, because these
types only produce primocanes from the crown (Figure
13). When using plastic or weed mat mulch, irrigate
plants under the mulch with a drip or soaker hose.

Irrigation
Blackberries need adequate water to thrive, either
from irrigation or rainfall. Fruit is made up of mostly
water, so sufficient irrigation during fruit production
is essential for the best yields and fruit quality. Newly
set plants do not have well-developed root systems,
so plants can be easily stressed. Irrigate several times
Photo: Bernadine Strik, © Oregon State University a week or as needed so that the root zone and soil
Figure 12. Berries grown in raised beds in the Willamette Valley. are thoroughly wetted but standing water does not

9
accumulate. Established blackberry plants typically
require from 1 to 1.5 inches of water per week during
the growing season, depending on plant vigor, stage of
growth, soil type and weather. Monitor your irrigation
carefully, whether applied by hand, sprinklers or drip
systems, to ensure you are adequately watering. With
each irrigation, wet the soil to a depth of 0.5 to 1 foot.
The rooting area should be wet enough that the soil
does not fully dry out between irrigation cycles. Sandy
soils require more frequent watering than heavier soils.
You can dig down into the soil to check if the soil is wet
— but not too wet — between irrigations and is wet
down to about 1 foot.
Drip irrigation is ideal for blackberry production
because it can reduce weed problems, conserve water
and reduce diseases that are sometimes caused by
overhead sprinklers wetting the canopy. Irrigate with
a single line of drip irrigation per row with half-gallon
emitters spaced every 18 inches. You may also use a
soaker hose, provided you monitor soil moisture to
ensure the proper amount of water is being applied.

Photo: Bernadine Strik, © Oregon State University

Figure 15. You can use an anchor for an end post with any type
of blackberry to keep the post from bending or breaking.

inches in diameter and 6 feet above ground). Set metal

T-style posts every 15 to 20 feet in the row. Run one
high-tensile wire (generally 12-gauge) at the top of
the posts (almost 6 feet high) and a second wire 4.5
feet above the ground. Install wire-tighteners for each
Photo: Bernadine Strik, © Oregon State University wire at one end of the row and an anchor at each end
Figure 14. This trailing blackberry, shown in spring, is trained to a (Figure 15). You may also choose to add additional
two-wire trellis. wires (at 3 feet above ground, for example) if you want
to spread the primocanes out more when training (see
“Pruning and training,” page 14).
Trellising
Erect types
Blackberries require trellising to support the canes, Erect cultivars, whether summer-bearing or ever-
keep fruit off the ground and protect canes from bearing, benefit from a T-trellis (Figures 11, page 8, and
wind damage. The exception is ornamental, dwarf, 16, page 11). You can use a simple “T” trellis made using
everbearing, erect cultivars; these also produce much rebar with about a 1.5-foot-wide cross piece with twine
lower yields (see “Harvest,” page 13). The best trellis to or wire strung down each side of the row to support the
use depends on the type of blackberry. canes. However, it is often simpler and more effective to
construct a trellis with wooden or metal end posts that
Trailing types are well anchored (especially for longer rows). You can
Trailing blackberry cultivars must have a trellis purchase pieces that can be attached to metal T-posts
because their canes are not self-supporting. You only at many farm supply stores. These are attached using
need a simple two-wire trellis (Figure 14). Set treated U-bolts and have slots for wires. Run a wire down each
wooden or metal posts at each end of the row (3 to 4 side of the T-bar and add wire tighteners.

10
 Semierect types
This type of blackberry is more vigorous than
the others and benefits from a more robust trellis,
especially when grown in the Willamette Valley. If you
have planted a row of semierect cultivars, use a “double
T” trellis (Figure 17). Install wooden posts as described
above for trailing types, but place these more robust
posts in the row. Attach wooden 2x4s or metal cross
pieces (see erect types above) to form the cross arms.
Install one 4-foot-wide cross arm at the top of the post
and one 2- to 3-foot-wide cross arm 2 feet below it.
Use two high-tensile wires along the outside of the
row on each cross arm so that you have four wires
extending between the posts. If you only have one or
two plants, you can trellis and train these more like
what is described for trailing types.

Nutrient management
Healthy blackberry plants with sufficient fertilizer
nutrients have dark green leaves. Pale green or yellow
leaves indicate a problem with nutrients, insects or
disease. In particular, plants deficient in nitrogen
will have older leaves that are pale green or yellow
compared to younger leaves.
Photo: Bernadine Strik, © Oregon State University
Your blackberry plants need fertilizer in the planting
Figure 16. Use a T-trellis for summer-bearing and everbearing erect
blackberries. These everbearing erect blackberries are fruiting in late and establishment years. There are many types of solid
September in the Willamette Valley. (granular) and liquid inorganic and organic fertilizers
available. Most all-purpose garden fertilizers or organic
products contain P (phosphate) and K (potash) as
well as nitrogen (N). Some, such as feather meal,
also contain Ca (Calcium). Fertilizer sources range
considerably in their nutrient content. For example,
common inorganic fertilizers available for the home
garden include 16–16–16 (16% each of N, phosphate
and potash), 20–20–20, and various slow-release
sulfur-coated urea products. Organic sources include
cattle (0.6–0.4–0.5) and horse (0.7–0.25–0.6) manure,
yard-debris compost (1–0.2–0.6), cottonseed meal
(6–7–2), feather meal (12–0–0), bone meal (2–15–0)
and fish emulsion (3–1–1). Avoid using fresh manure
products after planting, as they may pose a food safety
risk.
The main nutrient needed by blackberry plants after
planting in all home garden soils is N. To ensure the
maximum availability of N to the plants, match the
application method to the type of fertilizer you are
using. Inorganic granular fertilizers are often applied
in equal portions throughout spring and summer to
maximize the efficiency of plant uptake and minimize
the risk of salt stress to the blackberry plants.
Granular organic fertilizers such as feather, soybean
Photo: Bernadine Strik, © Oregon State University or cottonseed meals require longer periods of time for
Figure 17. A double T-trellis supports Semierect blackberry at N to be available. Therefore, it’s best to apply granular
the Marion County Master Gardener’s demonstration garden in
organic fertilizers about a month before inorganic
Salem, Oregon.

11
 Photo: Bernadine Strik, © Oregon State University
Figure 19. These plants in their first year have been fertilized using an inorganic granular product.

fertilizers would be applied. In general, liquid fertilizers New plantings

are available relatively quickly to plants but may When fertilizing new plantings, divide the total
also move out of the root zone quickly. So, for liquid required N into three equal portions, the first starting
fertilizers, divide the total amount of N into smaller, two weeks after planting, the next one month later, and
more frequent applications, such as weekly (see below). the last one a month after that. When using organic
Fertilizer recommendations for N are given in weight fertilizer sources, apply the product relatively earlier as
of actual N per length of row for the year. How much described above. Make inorganic fertilizer applications
fertilizer to apply depends on the percentage of N more frequently on sandy soil, dividing the total
in the product. To calculate how much N to apply rate into more split applications, or use slow-release
during the year, divide the amount of N you need by products, such as many organic sources of fertilizer
the percentage of N in the fertilizer (Figure 18). For (see above).
example, if the recommendation is to apply 2 ounces In the planting year, fertilize trailing and semierect
of N and you are using 16–16–16 fertilizer (16% each blackberries with 1 to 1.4 ounces N per plant,
of N, phosphate and potash), the calculation would be depending on soil type and plant vigor. Fertilize erect
2 ounces ÷ 0.16 (decimal equivalent of 16%), or 12.5 blackberries with 2 ounces N per 10 feet of row. Divide
ounces of the fertilizer product. In another example, if these total rates as described above.
you wanted to use soybean meal (6–2–1), you would
need about 33 ounces, or 2.1 pounds of product (2 Adjust fertilizer amount or rate and timing,
ounces ÷ 0.06). depending on how well plants are growing and your
growing region. Broadcast granular fertilizer over
the soil surface, spreading it evenly in an area a little
wider than the row width (Figure 19). Irrigate after you
Figure 18. Calculating fertilizer applications fertilize.
To calculate how much N to apply, divide the In raised beds, use a similar rate and timing of
amount of N needed by the percentage of N in applications. Common slow-release garden fertilizers
your fertilizer. and soluble products (those added to water) list
recommended rates on their product labels that should
work well for blackberry. Fish fertilizer is salty and will
2 oz. 16–16–16
injure plants unless the product is diluted 1:10 (1 part
÷ = 12.5 oz
fertilizer
fish to 10 parts water) prior to using.

Established plantings
0.16 For each year after the planting year, fertilize
summer-bearing trailing, erect and semierect
Scale by Ralph Schmitzer/Noun Project
Fertilizer bag by ic2icon/Noun Project blackberries with 1.5 ounces of N per plant or 3
ounces of N per 10 feet of row per year. Fertilize

12
everbearing erect blackberries with 3 ounces N per 10 to increase soil pH in the Willamette Valley and
feet of row. southwestern Oregon. Add elemental sulfur in central
Divide the fertilizer into two applications, applying or eastern Oregon to decrease soil pH and maintain it
the first in late March to early April. (This is based on within the desired range for blackberries.
the approximate timing of when primocanes start to
grow in the Willamette Valley; adjust the timing for Harvest
other growing regions.) Make the other application
about six weeks to two months later (in late May to Pick blackberry fruit by gently holding the berry and
early June, for example). Make fertilizer applications moving it up or down, rather than pulling on it. Ripe
more frequently on sandy soil, dividing the total blackberry fruit will separate easily from the stem when
rate into more split applications, and apply organic using a gentle breaking motion (Figure 20). The fruit
sources of fertilizer earlier, as described above. of most cultivars changes from a full shiny black to a
Semierect and everbearing blackberries may require dull black when fully ripe. Choose these dull-black fruit
an additional 0.5 ounce of N per plant or 1 ounce of when picking (Figure 21). Shiny black fruit are high in
N per 10 feet of row in six weeks to two months (mid- acid with comparatively less flavor and sweetness than
to late July in the Willamette Valley, for example) to dull black fruit.
ensure there is adequate fertilizer N available for the In general, pick blackberries every four to seven
later fruiting period. days, depending on the cultivar and the weather. Wash
Broadcast granular fertilizer products over the your hands before picking into clean containers. Pick
soil surface in the row area (about 2 to 3 feet wide, regularly. This not only helps ensure you collect berries
centered on the row). Irrigate immediately after at their optimal ripeness but also reduces insect pests
fertilization. and diseases that are more prevalent on overripe fruit
(see “Common problems,” page 19). Check plants more
A well-managed plant should have healthy green frequently in warmer or rainy weather. If an extended
leaves with good primocane growth (a good number period of rain is forecast, pick any berries that are not
per plant and a normal length for the cultivar and quite fully black; rain may dilute flavor and lead to fruit
the growing region). Pale green or yellow primocane rot. Try to avoid picking when fruit is wet from dew, fog
leaves, particularly toward the base of the cane, could or rain, and don’t wash it before storage. Wet fruit will
indicate N deficiency. decay faster. Refrigerate fruit immediately to keep it
Monitor soil pH every few years. Add lime in fall fresh longer.

Photo: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figure 20. Pick ripe blackberry fruit with a gentle breaking motion. Figure 21. Ripe blackberries are dull black in color.

13
 Photo: Bernadine Strik, © Oregon State University
Figure 22. ‘Marion’ trailing blackberry at the beginning of the fruiting season.

Everbearing erect cultivars are the only type that

produces in the planting year, producing a small crop,
depending on initial plant size. All types will produce a
“baby” crop the next year, and the third year they will
be in mature or full production.
Expected mature blackberry yields are 10 to 13
pounds per plant for trailing cultivars (Figure 22) and
25 to 35 pounds per plant for semierect cultivars.
Erect types will yield 18 to 28 pounds per 10 feet of
row. Yield depends on cultivar, planting health and
production region, which affects primocane growth or
vigor and risk of winter cold injury.
You’ll know it’s time to prepare for a new planting when:
• A planting becomes less vigorous (when it produces
fewer or weaker new primocanes).
• Fruit size is less than typical for the cultivar.
Photo: Bernadine Strik, © Oregon State University
• Your plants have disease or pest problems that may Figure 23. In the planting year, train trailing blackberry as the
not be controlled. primocanes grow.
Remove plants in late summer or fall. Purchase new,
certified disease-free plants. Since there are very few Trailing blackberries
soilborne pest problems in blackberry, it is usually not In the planting year of trailing blackberries, train
necessary to rotate plantings. However, be aware of the primocanes to the trellis as they grow in most
pest problems and rotate the planting if needed (see regions of the Willamette Valley (Figure 23). Bundle
“Common problems,” page 19). them together and use twine to attach them straight
up to the top wire; wrap them around the two wires,
Pruning and training spreading out the canes, if they grow taller. These
primocanes will overwinter and produce fruit as
For detailed explanations and video floricanes next year. In colder or more exposed yards,
demonstrations of pruning and training methods from you can leave the primocanes in a bundle on the soil
planting through maturity in each type of blackberry, surface through the winter — the canes will be less
see the online course Pruning and Training Blackberries, exposed to the elements on the soil surface. Then
https://workspace.oregonstate.edu/course/pruning- train them onto the trellis wires in late winter, before
blackberries. bud break.

14
 Dead floricanes

Primocanes

Photo: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figure 24. After harvest is complete, remove the dead floricanes, Figure 25. Train primocanes of trailing blackberry in late
which are visible on this trailing blackberry. August, dividing canes into two bundles and wrapping them on
the trellis wires.

In all subsequent years, plants will have fruiting

canes (floricanes) trained on the trellis that flower and
fruit in the spring and summer, and new primocanes
will begin growing from the crown of the plant (Figure
5, page 3). In most trailing cultivars, the primocanes
will “flop” over once they are about 3 feet long and
will continue to grow along the ground through the
season. Train these primocanes in a bundle underneath
the canopy of the floricanes so they are out of the way
and are less likely to be damaged as they grow (Figure
13, page 9). Use wire hoops, stakes or tie tape to keep
the primocanes in a bundle. Training will be easier if all
of the primocanes from each plant are trained in the
same direction so they are less tangled with those from
the adjacent plants; this is less important for thornless
cultivars. In some cultivars, primocanes will grow 15 to
20 feet long in the Willamette Valley.
After fruit harvest, remove the dying floricanes
(Figure 24) by pruning them at their base at the crown;
this is called “caning out.” Cane out immediately
after harvest (generally by the end of August in Photo: Neil Bell, © Oregon State University

the Willamette Valley). Cut the dead floricanes at Figure 26. ‘Boysen’ trailing blackberry in the Willamette Valley,
shown after training in late autumn.
their base, taking care to not cut any of the green
primocanes. Also cut the dead floricanes in various
places on the training wires to ease removal and pull without damaging or kinking some canes during the
them from the trellis. Then train the primocanes onto process; however, taking care during training will
the trellis. Train by dividing the primocanes from each improve yield. Secure the canes to the trellis using
plant into two bundles (Figure 25). Loop half the canes bailer’s twine or ties, if needed (Figure 25). You may
in one direction from the upper to lower trellis wires, also spread out canes more on multiple wires and tie
bringing them back towards the plant with one or two canes individually; this promotes good bud break and
twists; loop the other half in the opposite direction. yield (Figure 26). Remove canes that are too short.
It is nearly impossible to train the long primocanes There will be additional growth on these primocanes

15
 from training in August to frost in fall. Tuck or tie these
to the trellis in early to late November, when plants are
dormant.
In colder, higher elevation sites or in areas with
high wind, it may help to leave the canes on the
ground (Figure 27) and train them in late February
(Figure 28), well before bud break. This way, canes
are not exposed to colder temperatures or high winds
during winter, which can injure them (see “Common
problems,” page 19).

Summer-bearing erect
and semierect blackberries
For floricane-fruiting (summer-bearing) erect
and semierect blackberries, canes may trail along the
Photo: Bernadine Strik, © Oregon State University
ground in the first year after planting. Don’t worry; this
Figure 27. Trailing blackberry primocanes left on the soil to
reduce risk of winter cold injury. Canes will be trained in late
is normal, and the canes will become stiffer as the plants
February. age. Once plants are in their second growing season,
prune primocanes and floricanes as described below.
The primocanes of erect and semierect blackberries
require pruning during the growing season; this is
called tipping. Tipping erect and semierect blackberry
A primocanes during the growing season increases yield
four- to fivefold and makes the plants easier to manage.
Tip the primocanes in late spring or early summer
by removing the top 3–6 inches (Figure 29A). Top
them to a height of about 3 feet (erect) to 4.5 feet
(semierect). You will need to go over the planting
multiple times throughout early summer to catch all of
the primocanes. The tipped primocanes will produce
branches (Figure 29B).
Erect blackberry cultivars will send up primocanes
(suckers) from buds on their roots. Remove any suckers
Photos: Bernadine Strik, © Oregon State University
that are outside the 12-inch-wide hedgerow by pruning,
Figure 28. Trailing blackberry after training in late winter. hoeing or rototilling (Figure 11, page 8). Remove suckers

A B
Photos: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figures 29A and 29B. Tipping of primocanes (A) in erect and Figure 30. Semierect blackberry before primocane pruning
semierect blackberries leads to branching on primocanes (B). in winter.

16
 Photo: Bernadine Strik, © Oregon State University
Figure 32. Erect, summer-bearing blackberry with little pruning
of primocane branches. The plants are shown in early spring
after bud break on floricanes.

Everbearing erect blackberries

If you have the space, it is best to grow everbearing,
erect blackberry cultivars only for the primocane crop
(“single crop”) and to grow other types for the floricane
or summer crop. Producing a floricane crop (“double
Photo: Bernadine Strik, © Oregon State University crop”) on everbearing cultivars reduces and delays the
Figure 31. Erect, summer-bearing blackberry after primocane primocane crop, making it too late to harvest much of
pruning in winter. the fruit before fall rains or frost. However, if space is
tight or you are growing them in a container, double
frequently during the season as needed. Tuck the cropping will produce fruit over a longer period of
remaining primocanes between the trellis wires. time. Each strategy calls
Floricanes may be removed after fruit harvest in for different pruning
late summer (in erect cultivars) or in winter (both methods.
types). Pruning in winter involves caning out the dead
Single crop
floricanes (if you didn’t do so in summer), and pruning
and training the primocanes. Remove dead floricanes You can grow
by pruning them at their base. On the remaining everbearing erect
primocanes (Figure 30, page 16), remove any damaged blackberries for only a
or diseased wood and use pruners to shorten the primocane or late-season
lateral branches on the primocanes to a length of 1.5 crop. This is common
to 2.5 feet (erect cultivars, Figure 31) or 2.5 to 4 feet when you have the space
(semierect); longer primocane branches may be trained to grow both summer- Photo: Bernadine Strik,
if the trellis can support it (Figure 32). If needed, tie bearing and everbearing © Oregon State University

canes or branches to trellis wires to minimize wind blackberries. You will Figure 33. Erect, everbearing
damage and to support these canes when they fruit get a higher yield on the blackberry pruned for a single
floricanes of summer- crop. Old canes were cut to
next season.
In the Willamette Valley and southwestern Oregon, bearing cultivars, which is stubs in late winter. The photo,
prune any time from December through February. In an advantage if you like to taken in spring, shows early
primocane growth.
colder production regions such as central, eastern, make jam or freeze fruit.
and southeastern Oregon, prune as late as possible in If you are growing everbearing blackberries for a
winter (such as early March) to reduce risk of winter single crop, cut all the canes to just above ground
cold injury and remove any cold-damaged tissue (see level in late winter (March). Primocanes will emerge
“Common problems,” page 19). in the spring (Figure 33). Tip the primocanes in late

17
 minimize the risk of damaging any primocanes that
may be flowering.
During the growing season, tip the primocanes as
described above for a single crop and maintain the
hedgerow to a width of about 12 inches. Tuck the
remaining primocanes between the trellis wires as they
grow.
Pruning in winter involves caning out the dead
floricanes, if you didn’t do so in summer, and pruning
the primocanes. In the Willamette Valley, prune
anytime from December through February. However,
in colder production regions such as central, eastern,
and southeastern Oregon, prune as late as possible in
winter (early March) to reduce the risk of winter cold
injury and to remove any cold-damaged tissue (see
“Common problems,” page 19).
A B
Cane out any dead floricanes by cutting them at their
Photos: Bernadine Strik, © Oregon State University
Figures 34A and 34B. Erect, everbearing blackberry growing in a base; these canes will be shorter than the primocanes
container in the first growing season. The primocane is being tipped and will be dead from their tip to their base, with
to about 3 feet high (A) so that branches are produced (B). dead fruiting laterals evident. On the remaining
primocanes, remove the dead tips on the branches
spring or early summer by removing the top 6–12 and any unbranched primocanes; these portions of
inches. Top them to a height of about 3 feet (Figures the canes fruited in late summer to fall. Cut off the
34A and 34B). You will need to go over the planting dead tip by pruning a couple of nodes below the dead
multiple times throughout early summer to catch portion (Figures 35A–C). Do this for all canes in the
all of the primocanes at the right stage. The tipped row. The crop in early summer will be produced on
primocanes will produce branches that will flower these floricanes. The late-summer-to-fall crop will
and fruit starting in late summer (Figure 34B). Fruit be produced on the top portion, or branches, of new
production will end when killing frosts occur. Prune primocanes that emerge.
again in late winter by cutting all canes back to just
above the ground. Pruning in containers
During the growing season, keep the hedgerow If you are growing summer-bearing or everbearing
about 12 inches wide by removing suckers outside this blackberries in a constructed raised bed, prune your
width and tucking the remaining primocanes between planting as described above.
the trellis wires (Figures 11, page 8, and 16, page 11).
Double crop
If you are growing
your everbearing Dead fruiting portions
blackberries for a on primocane branch
double crop (floricane
and primocane crop),
you will need to
prune out the dying
or dead floricanes
after harvest. Cane
out immediately after
harvest only if there
are cane diseases
evident on the
dying floricanes (see
“Common problems,” A B C
page 19). Otherwise, Photos: Bernadine Strik, © Oregon State University
leave caning out Figure 35. Erect, everbearing blackberry growing in a container for a double crop. (A): Before pruning the
until winter so you primocane. (B). Removing dead branch tips. (C): After pruning.

18
 hardy and cannot be grown in central, eastern or
southeastern Oregon without cultural practices to
protect primocanes over winter.
In the Willamette Valley and warmer regions within
southeastern Oregon, it is usually not necessary
to protect trailing blackberry plants from cold
temperatures. However, you may need to take action
when unusually cold temperatures are forecasted
and plants are not fully dormant. This could occur in
late fall (for example, a chill of 20 ºF in November), in
midwinter (15 ºF in December/early January), or after a
particularly warm period in late winter (20 ºF). In these
instances, you can protect primocanes on the trellis
with a row cover (Figure 37), also called a floating row
cover, frost cloth or spun-bound cover. Place the row
cover over the trained canes in midafternoon, leaving
it on until after the cold spell has passed. If you live
in a colder region in the Willamette Valley or at high
elevation, training primocanes in late winter should
provide sufficient cold protection (see “Pruning and
training,” page 14).
Photo: Bernadine Strik, © Oregon State University You can grow trailing cultivars outside the
Figure 36. Erect, everbearing blackberry growing in a Willamette Valley and colder areas of southern Oregon
container in the first growing season in the Willamette Valley. with some considerations for winter protection. Train
Fruit are being produced on the tip of each primocane branch primocanes only in late winter (see “Pruning and
in September. training,” page 14). In areas with little winter rainfall,
you can mulch canes with straw. Remove the straw
When growing an everbearing erect blackberry after risk of severe cold has passed and buds are
plant in a container (Figure 36), prune in winter as starting to break in late winter or spring. In areas with
described above. Also thin the primocanes during winter rainfall, use row covers to cover primocanes as
the growing season, in addition to tipping them as needed when it gets cold (see above). In some regions,
described above. Wait until the earliest primocanes you may need to mulch the crown with straw.
are about 2 feet tall. Thin the primocanes to keep no Erect and semierect cultivars do not need any form
more than four new primocanes per 20- to 30-gallon of cold protection in most regions of Oregon; some
container; remove primocanes that are thinner or cane damage may occur in particularly cold winters.
shorter than average and those at the outside edge of
the container.

Common problems
Weather-related problems
Blackberry plants adapted to your region are cold
hardy but may still be susceptible to frost damage to
growing plant parts in late fall or late winter to early
spring. In some winters, cold damage may occur when
plants are not growing or are dormant.
Winter cold injury
The temperature at which blackberry canes or buds
are damaged depends on the time of the year, the
weather preceding the freeze, the type and the cultivar.
When cold damage is severe, no fruit will be produced.
Minimize risk by choosing types and cultivars that Photo: Bernadine Strik, © Oregon State University
are adapted to your hardiness zone (see “Blackberry Figure 37. A rowcover protects trailing blackberry from a
cultivars,” page 6). Trailing cultivars are the least cold forecasted cold spell in late winter.

19
 Cold damage to canes in all blackberry types is
most common at the tip of the cane — the portion Dead cane tops
that grew and matured last — prior to winter (Figure
38). Damage to blackberry buds may occur anywhere
on the cane. On cold-damaged canes, fruiting laterals
will either not grow (Figure 38) or they will start to
grow and will then collapse because the cane cannot
support their further growth. Cold damage on canes
may be reflected in damage to the cane (Figure 39)
or to the buds. If buds on primocanes are killed by
winter cold, bud break will be sporadic in the spring,
leading to a reduced number of fruiting laterals on the Photo: Bernadine Strik, © Oregon State University
floricane in spring and lower yield. Figure 38. Winter cold injury to top cane sections of trailing
blackberry.
Frost injury
Frost will injure open flowers at 30 °F. While frost
injury to flowers on the floricane is not common in the
Willamette Valley, it may occur in other production
regions. In central and eastern Oregon, frost can occur
any time during the growing season, which may injure
flowers and reduce yield. You can use frost cloth or row
cover in spring to try to reduce frost injury. Frost in fall
will curtail fruiting on the primocane in everbearing
cultivars in all production regions. A B
Photos: Bernadine Strik, © Oregon State University
Poor pollination
Figure 39. Cane sliced to show healthy cane and bud (A) cold-
On rare occasions, rain or cool weather during damaged cane (B).
bloom can reduce fruit set by limiting pollination
directly or indirectly through reduced bee activity.
But this is not common in blackberry. Blackberry
flowers produce a lot of nectar and are attractive to
all pollinators (Figure 40).
Sun damage to fruit
Intense heat, particularly with low humidity, may
lead to ultraviolet damage to blackberry fruit. Sections
of the berry exposed to the sun bleach white (Figure
A B
41) and become dry or dark red and soft (called
“jamming”). Cultivars differ in sensitivity. In hotter Photos: Bernadine Strik, © Oregon State University
regions, use shade cloth to protect developing fruit. Figure 40. Pollinators in blackberry include a honey bee on a flower
(A) and a painted lady butterfly (B), both shown on a ‘Marion’
blackberry in the Willamette Valley.
Weeds and weed management
Weeds compete with blackberry plants for water
and nutrients, so it is important to keep weeds out of
the row. Within the row, new primocanes can be easily
broken. In trailing cultivars, primocanes need to be
bundled and trained on the soil, so pull any weeds by
hand to avoid tangling. In erect types, hoe or cultivate
to remove weeds and unneeded primocanes outside
of the in-row area. Mulch in the row, such as straw,
sawdust, bark or weed mat (Figure 13, page 9), may
help control weeds (see “Mulching,” page 9).
Chemical weed control options suitable for
Photo: Bernadine Strik, © Oregon State University
blackberry plantings are limited in the home garden.
Figure 41. Symptoms of UV and sunburn damage in
Be extremely careful when using glyphosate (Roundup)
blackberry fruit.
to kill weeds anywhere near your planting. Blackberry

20
 Photo: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figure 42. Erect blackberry showing Roundup injury to new Figure 43. Symptoms of red berry mite in Semierect blackberry
primocanes in the spring (strap-like, twisted, pinkish growth). (sections on berry with red, hard drupelets).

plants are sensitive to this herbicide (Figure 42). laterals grow. The mite is about 4 mm long and feeds
For detailed information on specific weeds and weed at the base of berry drupelets as they develop, which
control, see the PNW Weed Management Handbook, prevents the red drupelets from turning black during
https://catalog.extension.oregonstate.edu/weed. ripening. The affected drupelets remain hard and red
(Figure 43), not soft and red, which is a symptom of UV
Vertebrate pests damage (page 20).
Birds, deer, squirrels and mice can be nuisance Raspberry crown borer
pests for blackberries. If you are not able to fence your The raspberry crown borer can be found in the
entire property or garden area, netting can provide Willamette Valley. The adult is a clear-winged moth
protection and is effective against birds as well. that resembles a wasp. Larvae bore into the canes and
crown of blackberry and raspberry plants. The life cycle
Insect pests requires two years to complete. Symptoms of severe
infestations include dead or dying plants (Figure 44).
Spotted wing drosophila There is no control other than to rogue out or remove
The most important insect pest in blackberry infested plants and destroy or burn them, where
production is the spotted wing drosophila, or SWD. permitted.
This pest is much less prevalent or not found in central,
eastern or southeastern Oregon. This vinegar fly looks
a lot like the common fruit fly. The female lays eggs in
developing fruit, generally after it first develops some
color. The larvae feed inside the berry while the fruit is
ripening without much evidence of the damage from
the outside of the fruit. Populations of SWD build
up during the season, so late-fruiting cultivars (such
as erect and semierect cultivars) are more prone to
damage. You may use fine exclusion netting to prevent
adults from reaching the berries. For more information
on how to control and manage this insect, see the SWD
publications listed in “Resources,” page 24.
Red berry mite
Red berry mites are most common on late-fruiting,
summer-bearing blackberries, such as semierect Photo: Neil Bell, © Oregon State University
cultivars. Adult mites overwinter in the bud scales. Figure 44. The weak plants at the back of this row of summer-
After bud break, they migrate to berries as the fruiting bearing red raspberry show injury from raspberry crown borer.

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 A B A B
Photo: Patrick Jones, Photo: Bernadine Strik, Photos: Bernadine Strik, © Oregon State University
© Oregon State University © Oregon State University
Figure 47A. Infected canes Figure 47B. Spotting from
Figures 45A. Red raspberry Figure 45B. Cutting a show lesions of purple blotch. infections with Septoria cane
primocanes showing tip death primocane lengthwise just and leaf spot
caused by larval feeding of the below a dead tip reveals a larva
rose stem girdler. of the rose stem girdler.

Rose stem girdler Other insects that can be problematic in blackberries

The rose stem girdler is a recent pest to blackberry include raspberry beetle (raspberry fruit worm), stink
in the Willamette Valley. The adult is a small, metallic- bugs, root weevils, leaf-roller larvae, leaf hoppers,
colored beetle. Larvae burrow along the cane length, spider mites and aphids, depending on your production
creating visible bumps. Canes can die above the region. Check with your local OSU Extension office if
feeding point (Figure 45A). When you identify this type insects become a problem. Also see the PNW Insect
of damage and see the larva (picture 45B), cut below Management Handbook, https://catalog.extension.
the infected cane section and burn (where permitted) oregonstate.edu/insect.
or destroy these canes to kill the larvae. It’s important
to do this before the adults emerge — generally in April Diseases
or May in the Willamette Valley.
Septoria leaf spot and purple blotch
Brown marmorated stink bug Most trailing blackberry cultivars are sensitive to leaf
Brown marmorated stink bug, or BMSB, is an and cane disease. Purple blotch lesions can be seen on
emerging pest in blackberry and a wide range of other primocanes in winter and spring. Lesions can be as long as
fruit crops. While it is not considered a major pest in 2 inches and are purple with a red margin. This disease may
this crop, if you have high populations of BMSB in your also occur on semierect cultivars (Figure 47A). Septoria
yard, you may see some fruit damage, particularly in leaf spot is visible on fruiting lateral leaves in spring (Figure
late-season cultivars. Nymphs (Figure 46A) and adults 47B). At first, spots are small and purplish in color. They
feed on developing drupelets, causing them to collapse later turn brown. In older leaf spots, centers are whitish
or change color (Figure 46B). with brown to red borders. Spots may also occur on canes.
While these cane and leaf diseases may reduce bud break
and yield if severe, generally no pest control measures
are needed with good
pruning, training and weed
management.
Botrytis fruit rot and
cane disease
Blackberry fruit are
susceptible to gray mold
(Botrytis fruit rot) if there is
A B overhead irrigation or rain
Photos: Bernadine Strik, © Oregon State University
during the fruiting period
Figure 46A. Brown Figure 46B. Fruit damaged by
(Figure 48). Remove and Photo: Bernadine Strik,
marmorated stink bug nymphs brown marmorated stink bug. destroy diseased fruit from © Oregon State University

feed on fruit of an everbearing the planting as soon as it Figure 48 . Botrytis gray mold on
erect blackberry. is visible. trailing blackberry fruit.

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 Gall

Photo: Bernadine Strik, © Oregon State University Photo: Bernadine Strik, © Oregon State University
Figure 49. Cane and leaf rust in blackberry. Figure 50. Symptoms of crown gall in erect blackberry. Note the
gall growth at the crown.

Cane and leaf rust Although most blackberry cultivars are tolerant
Cane and leaf rust occurs in western Oregon in spring to heavy soil and will not get root rot, the trailing
when a significant rainy period follows a warmer period. cultivar ‘Columbia Star’ may get this disease under
It is not systemic in the plant. Symptoms include yellow poor growing conditions. If you decide to replant
spots on the top of the leaves and then yellow fungal in another area of your yard using newly purchased
spots on the underside of leaves on the floricane (Figure plants, check which crop plants may be susceptible to
49). If left to advance, rust can progress to the berries, phythophthora root rot before planting in your old,
or the berries will die without leaves to support their infested spot.
development. If the disease occurs, remove infected Other diseases may become problematic in
floricanes and destroy or burn them where permitted. blackberries. If disease becomes an issue, check
In fall, rake and destroy or burn the fallen leaves. Do with your local OSU Extension office for control
not tie primocanes until after leaves fall. This breaks the recommendations. Control methods are also outlined
disease cycle so that the rust spores do not spread to in the PNW Plant Disease Management Handbook,
the primocanes that are growing. https://catalog.extension.oregonstate.edu/plant.

Crown gall
Crown gall bacteria may come into your planting
with infected plants or persist in soil as a result of
previously infected plants. Symptoms appear as small,
rough ridges or elongated overgrowths of gall tissue
(Figure 50). Galls frequently cause canes to split open.
Once present in the soil, the bacteria can survive for
years. This disease is spread by splashing rain, overhead
irrigation water, pruning tools, wind, insects, hoeing and
rototilling. Disinfect tools after pruning or after working
in an infected patch. Prune only during dry weather. If a
plant is infected, remove it. Buy only certified disease-
free plants.
Root rot
Phytophthora root rot, a soilborne disease, is
aggravated in wet, heavy soil. Symptoms include
primocanes dying in midsummer and fruiting laterals Photo: Bernadine Strik, © Oregon State University
collapsing just prior to or during fruit harvest (Figure Figure 51. Symptoms of phytophthora root rot in ‘Columbia
51). Infected plants will die over a period of time. Star’ trailing blackberry. The floricanes are collapsing.

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Resources
A Detailed Guide for Testing Fruit for the Presence of Spotted Wing Drosophila (SWD), EM 9096,
https://catalog.extension.oregonstate.edu/em9096
Acidifying Soil for Blueberries and Ornamental Plants in the Yard and Garden, EC 1560,
https://catalog.extension.oregonstate.edu/ec1560
Acidifying Soil in Landscapes and Gardens East of the Cascades, EC 1585,
https://catalog.extension.oregonstate.edu/ec1585
Applying Lime to Raise Soil pH for Crop Production—Western Oregon, EM 9057,
https://catalog.extension.oregonstate.edu/em9057
Eastern Oregon Liming Guide, EM 9060, https://catalog.extension.oregonstate.edu/em9060
Growing Berries on the Oregon Coast: An Overview, EM 9177, https://catalog.extension.oregonstate.edu/em9177
Growing Berries on the Oregon Coast: Raspberries and Blackberries, EM 9180,
https://catalog.extension.oregonstate.edu/em9180
Improving Garden Soils with Organic Matter, EC 1561, https://catalog.extension.oregonstate.edu/ec1561
Laboratories Serving Oregon: Soil, Water, Plant Tissue, and Feed Analysis, EM 8677,
https://catalog.extension.oregonstate.edu/em8677
Oregon State University Spotted Wing Drosophila information page, http://spottedwing.org
Pacific Northwest Insect Management Handbook, Pacific Northwest Plant Disease Management Handbook, and Pacific
Northwest Weed Management Handbook, revised and reissued annually. http://pnwhandbooks.org
Pruning and Training Blackberries online course, https://workspace.oregonstate.edu/course/pruning-blackberries
Blackberry Cultivars for Oregon, EC 1617, https://catalog.extension.oregonstate.edu/ec1617
A Guide to Collecting Soil Samples for Farms and Gardens, EC 628, https://catalog.extension.oregonstate.edu/ec628
Soil Test Interpretation Guide, EM 8713, https://catalog.extension.oregonstate.edu/ec1478
Raised Bed Gardening, FS 210, https://catalog.extension.oregonstate.edu/fs270
Selecting Berry Crop Varieties for Central Oregon, EC 1621, https://catalog.extension.oregonstate.edu/ec1621

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