Plant layering

Plant layering is a method of asexual plant propagation where a stem is encouraged to

develop roots while it is still attached to the parent plant. Once the roots form, the new plant
can be cut away and planted separately. Layering is commonly used for plants that are
difficult to propagate through seeds or cuttings.
Layering is an ancient technique for vegetative propagation. It was used extensively in
European nurseries from the 18th to the early 20th century for propagating woody shrubs and
tree species. It is no longer a primary nursery technique for propagating most plants, but does
provide some advantages for propagating native species where time or resources may be
scarce.

The two main types of plant layering are:

1. Ground Layering (Soil Layering): In this method, a stem is bent down to the ground
and buried under soil, with the tip of the shoot exposed. Over time, roots form at the
buried section of the stem. Once the roots are established, the stem can be cut from
the parent plant and transplanted. Examples of plants that use ground layering include
strawberries, blackberries, and ivy.
1. simple layering
2. tip layering
3. serpentine/Compound layering
4. trench/continuous layering
5. mound stood layering
2. Air Layering: This method involves wounding or removing a section of bark from
the stem of a plant and wrapping it with moist sphagnum moss and plastic to
encourage root formation. The stem remains attached to the parent plant while roots
develop. Once roots have formed, the new plant can be cut and planted. Air layering is
commonly used for larger, woody plants like rubber trees, magnolias, and citrus trees.
1.Simple Layering
Simple layering involves bending a low-growing, flexible branch to the ground, burying
part of the stem under soil, and leaving the tip exposed. Over time, roots form at the
buried section, allowing the new plant to be separated from the parent.
Simple layering can be accomplished by bending a low growing, flexible stem to
theground. Cover part of it with soil, leaving the remaining 6 to 12 inches above the
soil.Bend the tip into a vertical position and stake in place (Figure 1). The sharp bend
willoften induce rooting, but wounding the lower side of the bent branch may help
also.Simple layering can be done on most plants with low-growing branches. Examples
of plants propagated by simple layering include climbing roses, forsythia,
rhododendron,honeysuckle, boxwood, azalea, and wax myrtle.
Simple layering can be done in early spring using a dormant branch, or in late
summer using a mature branch. Periodically check for adequate moisture and for the

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formation of roots. It may take one or more seasons before the layer is ready to be
removed for transplanting

Steps:
• Select a healthy, flexible stem from the parent plant.
• Bend it to the ground and make a small wound or notch at the point where it touches
the soil to encourage rooting.
• Cover this portion with soil, leaving the tip of the stem exposed.
• Keep the soil moist to promote root development.
• Roots typically form within 1 to 2 months, depending on the species and
environmental conditions.
• Once roots are well-established, the new plant can be cut away and transplanted.
Example
• Hibiscus and Bougainvillea are commonly propagated using simple layering in Sri
Lanka due to their flexible branches.
• Time Duration: 1 to 3 months, depending on the species and environmental
conditions (warm, humid climates like those in tropical countries speed up rooting).

2. Tip Layering
In tip layering, the tip of a stem is bent and buried in the soil, allowing it to root at the
buried section. A new shoot emerges from the buried tip, and roots form along the stem.
Tip layering is quite similar to simple layering. Dig a hole 3 to 4 inches deep. Insert thetip
of a current season’s shoot and cover it with soil. The tip grows downward first,
then bends sharply and grows upward. Roots form at the bend. The re-curved tip becomes
anew plant. Remove the tip layer and plant it in late fall or early spring.Examples of
plants propagated by tip layering include purple and black raspberries, andtrailing
blackberries.

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Steps:
• Select a healthy stem and bend the tip into the ground.
• Cover the tip of the shoot with soil, leaving the rest of the stem exposed.
• Water regularly to maintain soil moisture.
• Once roots form and a new shoot emerges, the plant can be severed from the parent.
Example :
• Blackberries and Raspberries can be propagated using tip layering in tropical
climates. These plants are known to thrive in the highlands of Sri Lanka (e.g., Nuwara
Eliya).
• Time Duration: Usually takes about 4 to 8 weeks for roots to form, depending on the
species and local climate.

3. Serpentine/Compound Layering
Serpentine or compound layering involves burying multiple sections of a long stem while
alternating sections remain above the soil. Each buried portion forms roots, creating
multiple new plants from a single stem.
Compound (serpentine) layering is similar to simple layering, but several layers can result
from a single stem. Bend the stem to the rooting medium as for simple layering, but
alternately cover and expose sections of the stem. Each section should have at least
one bud exposed and one bud covered with soil. Wound the lower side of each stem
section to be covered (Figure 3). This method works well for plants producing vine-like
growth such as heart-leaf philodendron, pothos, wisteria, clematis, and grapes.
Steps:
• Select a long, flexible stem and bend it to the ground.
• Alternately bury and expose sections of the stem, creating several rooting points.
• Water consistently to encourage root development at the buried sections.

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• Once roots develop at multiple points, the stem can be severed between each rooted
section to create several new plants.
Example:
• Vining plants such as passionfruit (Passiflora) and money plant (Epipremnum
aureum) are often propagated using serpentine layering. These plants are widely
grown in home gardens and small farms across Sri Lanka.
• Time Duration: Roots typically form in 2 to 3 months, depending on plant species
and climate.

4. Trench/Continuous Layering
In trench layering, a long branch is placed horizontally in a trench and buried with soil.
Shoots grow vertically from nodes along the buried branch, and roots form at the buried
sections.
Also known as etiolation layering, trench layering is primarily used for fruit trees which
are difficult to propagate by other methods, and works best with plants whose buds will
break and grow under the soil, such as willows, viburnum, grapes and dogwoods.
Steps:
• Dig a shallow trench and lay a long, flexible stem horizontally in it.
• Bury the entire stem, leaving the tip exposed.
• Shoots will emerge from the nodes along the buried stem, and roots will form at these
points.
• Water consistently to maintain moisture in the soil.
• Once shoots have developed roots, they can be separated from the parent plant.
Example
• Durian (Durio zibethinus) and cinnamon (Cinnamomum verum) trees, which are
commonly grown in Sri Lanka, can benefit from trench layering. This method is ideal
for establishing multiple plants from a single tree.
• Time Duration: This method can take 3 to 6 months for full establishment, as it
involves multiple new shoots developing.

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5. Mound/Stool Layering
In mound (stool) layering, the plant is cut back, and new shoots that emerge are gradually
buried with soil to encourage rooting at the base. This technique is commonly used for
woody plants and shrubs.
Mound (stool) layering is useful with heavy-stemmed, closely branched shrubs and root
stocks of tree fruits. Cut the plant back to 1 inch above the soil surface in the dormant
season. Dormant buds will produce new shoots in the spring. Mound soil over the new
shoots as they grow.Roots will develop at the bases of the young shoots

Steps:
• Select a mature plant and cut it back to ground level in early spring.
• As new shoots emerge, mound soil around them as they grow.
• Continue adding soil to cover more of the shoot base as they grow taller.
• Roots will form at the base of the shoots as they are buried.
• Once well-rooted, the shoots can be severed from the parent plant and transplanted.
Example
• Tea plants (Camellia sinensis) are propagated using mound layering in the highlands
of Sri Lanka, where tea cultivation is widespread.
• Time Duration: 6 to 12 months, as this method typically takes longer due to the slow
development of roots in woody plants.

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Air Layering
Air Layering is a plant propagation technique where a section of a plant stem is encouraged
to develop roots while still attached to the parent plant. Unlike ground layering, air layering is
typically used for plants that have woody stems or are difficult to propagate by other
methods. It is particularly effective for larger plants and trees that do not bend easily to the
ground for traditional layering methods.
Process of Air Layering
1. Selection of the Plant:
o Choose a healthy, mature stem from the parent plant. The stem should be
around 1-2 years old and semi-woody.
o Air layering is most effective on plants that are difficult to propagate through
cuttings, such as woody trees, shrubs, and certain tropical plants.
2. Making the Wound:
o Select a section of the stem (usually 30-60 cm from the tip), and remove a ring
of bark (about 2-3 cm wide). This is called girdling. The removal of the bark
prevents the downward flow of carbohydrates, which accumulate at the
girdling site and stimulate root growth.
o Optionally, the exposed area can be treated with rooting hormones (auxins
such as indole-3-butyric acid or IBA) to enhance root formation.
3. Wrapping the Wound:
o Wrap the girdled area with moist sphagnum moss or coconut coir (which is
widely available in Sri Lanka). This medium helps retain moisture, ensuring
the plant can develop roots.
o The moss is then covered with a piece of plastic wrap to prevent moisture loss.
Secure both ends of the plastic with string or twist ties to keep it in place and
prevent water from evaporating.
o Optionally, the plastic can be covered with aluminum foil to protect the area
from excess sunlight, maintaining cooler conditions for root development.
4. Maintenance:
o It’s important to regularly check the air layer to ensure the moss remains
moist. This can be done by opening the plastic wrap and re-moistening if
necessary.
o Depending on the plant species and environmental conditions, root formation
can take anywhere from 4 weeks to 3 months.
o Tropical climates, like Sri Lanka’s, accelerate root formation due to warm
temperatures and high humidity.
5. Separation:

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 o Once a significant amount of roots has developed (this can be checked by
unwrapping the plastic), the new plant can be separated from the parent.
o Cut below the root mass, and the new plant is ready to be potted or
transplanted.
o It’s essential to acclimatize the new plant gradually to its new environment by
potting it first in a container for better root development before planting it
outdoors.
Time Duration:
• Root Formation: Air layering can take anywhere from 4 weeks to 12 weeks
depending on factors like plant species, environmental conditions, and care. In
tropical climates like Sri Lanka’s, the process may be quicker due to the optimal
warmth and humidity.
• Complete Transplant Readiness: After root formation, it’s advisable to leave the
plant in a pot for a few weeks to ensure strong root growth before transplanting.
Examples of Plants Suitable for Air Layering in Tropical Climates (Sri Lanka)
1. Rubber Tree (Ficus elastica):
o Widely grown in tropical countries like Sri Lanka, rubber trees are commonly
propagated through air layering. This method is often used when the plant
becomes too tall or when a new clone of the plant is required.
2. Mango (Mangifera indica):
o In Sri Lanka, mango trees are frequently propagated through air layering to
clone specific varieties that produce desirable fruits. This technique ensures
the new plant retains the characteristics of the parent tree, such as fruit size
and taste.
3. Citrus Trees (Citrus spp.):
o Air layering is a popular method for propagating lime, lemon, and orange trees
in tropical areas. This allows the production of new trees while preserving the
exact traits of the parent tree.
4. Guava (Psidium guajava):
o Guava is a commonly grown tropical fruit tree in Sri Lanka. Air layering is
used to produce multiple clones of high-quality guava trees, ensuring uniform
fruit production.
5. Durian (Durio zibethinus):
o Known for its large, spiky fruits, the durian tree is often propagated via air
layering in tropical regions like Southeast Asia and Sri Lanka.

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Figure 1. Method of wounding woody plants such as magnolia, gardenia, rose, fig and similar
plants. With a sharp knife, make two parallel cuts about 1 1/2 inches apart around the stem
and through the bark and cambium layer. Connect the two parallel cuts with one long cut (a)
and remove the ring of bark (b), leaving the inner woody tissue exposed (c).

Figure 2. Method of wounding plants having less woody stems in preparation for air layering.
This method usually is used on foliage plants such as the rubber plant, (Ficus benjamini and
Ficus elastica) and the dieffenbachia. (a) With a sharp knife, make a long upward cut from 1
1/2 to 2 inches long, almost to the center of the stem. (b) Insert a wood sliver, toothpick or
twisted piece of sphagnum moss into the wound to hold it open and prevent cut tissue from
reuniting. At this point, the wounded area may be dusted with one of the commercial rooting
compounds to speed up the rooting process. Such compounds, however, do not insure root
production on difficult-to-root varieties.

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Figure 3. Apply a handful of damp sphagnum moss so that it envelopes the wounded portion
of the stem. Tying the moss in place with string helps keep it in position while completing the
process. The sphagnum moss hould be soaked several hours to insure that it is thoroughly
moist. Squeeze out surplus water before using, since excessive moisture will result in decay
and deterioration of the plant tissue.

Figure 4. Using a sheet of polyethylene film approximately 6" X 12" or 8" X 12", depending
upon the size of the plant stem, wrap the ball of sphagnum moss using the butchers fold (see
insert) to secure a tight seal where the two ends of the sheet are joined.

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Figure 5. Draw the upper end of the film snugly around stem making sure that none of the
moss is exposed. Fasten securely with electricians tape, taking care that the tape extends
beyond the film and adheres to the stem. Repeat the procedure on the lower end, again
making sure there is a snug fit. Moisture must not escape and excess moisture must not enter
when watering or syringing the plants. Support the plant with stake or splint to prevent
breakage at the wounded area.

Figure 6. After the new roots have penetrated the moss ball and are visible on all sides, the
rooted branch may be removed from the parent plant. The rooting time will vary with plant
variety as well as the season in which it is performed.

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Figure 7. Remove the newly rooted plant from the parent plant with a sharp knife or pruning
shears, making the cut just below the ball of moss and roots. (Not illustrated) Carefully
remove the polyethylene film. Without disturbing the roots or removing the ball of moss,
plant in a container using a good potting mixture or plant in a well-prepared soil bed.

Figure 8. Placing a polyethylene tent over the newly potted plant for 4 to 8 days until the root
system is well established is helpful as it will aid in preventing excessive loss of moisture.
Keep the plant under a light shade and avoid direct sunlight until the new root system is well
developed.

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Advantages of Plant Layering
1. Cloning of Parent Plant:
o Layering produces plants that are genetically identical to the parent plant,
preserving desirable traits such as disease resistance, fruit quality, or specific
growth habits.
o Example: In Sri Lanka, mango (Mangifera indica) trees are often propagated
by air layering to clone high-yielding and good-quality fruit varieties.
2. No Need for Special Facilities:
o Layering doesn’t require elaborate infrastructure, greenhouses, or controlled
environments like tissue culture or grafting might. It can be performed in
outdoor garden settings with minimal tools.
o Example: In rural farming areas in tropical countries, plants like guava
(Psidium guajava) are propagated by layering without the need for special
propagation materials.
3. High Success Rate:
o Since the new plant remains attached to the parent plant, it receives a
continuous supply of nutrients and water, reducing the risk of failure due to
environmental stress.
o Example: Jasmine (Jasminum spp.) is propagated using simple layering due
to its high success rate with this method.
4. Minimized Stress on New Plants:
o The new plant is less stressed during the rooting process because it is still
connected to the parent plant. This makes layering ideal for plants that are
difficult to propagate through cuttings.
o Example: Rubber trees (Ficus elastica), commonly grown in tropical regions
like Sri Lanka, are often propagated using air layering, as they are difficult to
root through stem cuttings.
5. Multiple Plants from a Single Stem:
o Certain methods of layering, such as trench layering, allow multiple new
plants to be propagated from a single stem.
o Example: Black pepper (Piper nigrum) can be propagated using trench
layering in tropical climates to produce several new vines from a single long
stem.
Disadvantages of Plant Layering
1. Space-Consuming:

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 o Some types of layering, like trench and mound layering, require significant
space in the garden because long branches or stems are laid down or buried in
the ground.
o Example: Cinnamon (Cinnamomum verum) is layered using trench
layering, which requires a considerable amount of space to allow the long
stems to be placed in the soil.
2. Slow Process:
o Layering can take several weeks to months before roots form, depending on
the plant species and environmental conditions. This process is slower
compared to other methods like cuttings or tissue culture.
o Example: Durian (Durio zibethinus) propagated by air layering may take 3-
4 months to form strong roots in tropical climates.
3. Labor-Intensive:
o The process of preparing the plant for layering (e.g., removing bark for air
layering or burying sections for trench layering) can be labor-intensive,
especially for larger plants.
o Example: Setting up multiple air layers on citrus trees (Citrus spp.) in a
commercial orchard can take a significant amount of time and effort.
4. Limited to Specific Plants:
o Not all plants are suitable for layering. While it works well for woody and
semi-woody plants, herbaceous plants or plants with soft stems may not layer
successfully.
o Example: Herbaceous plants, such as some varieties of lettuce, are not
suited for layering techniques due to their weak stems.
5. Risk of Disease:
o When plant tissues are exposed (as in air layering) or buried (as in trench
layering), there is a risk of fungal or bacterial infections, especially in humid
tropical environments.
o Example: In tropical climates like Sri Lanka, fungal diseases can affect the
air layering process of plants such as jasmine if the moss or wrapping is too
wet.

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