Title: Propagation of ornamental plants by layering
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 Material Information
Title: Propagation of ornamental plants by layering
Series Title: Propagation of ornamental plants by layering
Physical Description: Book
Creator: Sheehan, Thomas J.
Publisher: Agricultural Extension Service
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Bibliographic ID: UF00084279
Volume ID: VID00001
Source Institution: University of Florida
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Resource Identifier: oclc - 216719695

Full Text

September 1955


Propagation of

Ornamental Plants

by Layering
T. J. SHEEHAN
Assistant Ornamental Horticulturist
JASPER N. JOINER
Assistant Horticulturist

In general, any method of producing a new plant that is identi-
cal to the parent plant in all respects is called vegetative or
asexual propagation. Since many of our woody ornamental
plants do not breed true from seed, it becomes necessary to re-
produce them by vegetative methods such as layering. Layerage
is a method of propagation by which new plants are formed while
still attached to the "parent" plant upon which they depend
for nutrients and water until roots develop. In this manner a
large plant usually can be developed in a relatively short time
and with less trouble than other methods of propagation.
Layering is a simple and relatively easy method of propagating
many woody ornamental plants and is ideal for homeowners and
nurserymen in rooting plants that are difficult to propagate by
either cuttings, grafting or seeds. In outdoor practice it is best
performed during spring and summer months, although it can
be done at any season of the year. Spring and summer layers
are usually rooted and ready for transplanting before the dor-
mant season.
The various types of layerage are air (Chinese, pot or mar-
cottage), tip (or simple), trench, mound (stool) and serpentine
(or compound). Air and tip layering are the most popular forms.

Air Layering or "Mossing Off"
Air layering (Fig. 1) is not a new form of propagation, as
many believe. It was practiced many centuries ago by the
Chinese and was called pot layering or marcottage. With the


AGRICULTURAL EXTENSION SERVICE
GAINESVILLE, FLORIDA


Circular 141





advent of polyethylene films this form of propagation has en-
joyed renewed interest among both amateurs and professionals.
The new wrapping materials eliminate tedious waterings and per-
mit ready evaluation of progress of root formation. Aluminum
foil and freezer wrapping paper are being used, in addition to
plastic films. There are complete air layering kits on the market
to make the job simple for amateur propagators.
Best results are obtained when young, maturing, vigorously
growing, healthy branches are selected for layering. Leaves on
selected branches should be exposed to the light, since these pro-
duce more carbohydrates and root faster. Branches from pencil
size up to about "/1 inch in diameter are best for air layering.
Quite often it is possible to select wood which would normally
be pruned in shaping the plant.
















Fig. 1.-AIR LAYERING-Progressive steps in making an air layer
(from left).

The propagator should have all the necessary tools on hand
before beginning the operations, because after the cut is made,
it should be wrapped quickly to prevent drying out and possibil-
ity of failure. The materials needed are few and relatively
inexpensive as compared to materials needed for other methods
of propagation. A sharp knife, double handful of damp sphag-
num moss, a six-by-eight inch sheet of polyethylene film and a
rubber band or a piece of twine are the important materials.
Craft paper or a piece of cloth can be used in addition if the
film is exposed to direct sunlight. Covering the film with cloth
prevents the sun from scalding or burning young developing
roots.





The first step is to remove leaves and twigs on the selected
limb for approximately three to four inches above and below
the point where the cut is to be made-this is usually from 12
to 15 inches or more below the tip of the limb.
Two methods of injuring the branch to induce rooting can be
used. Satisfactory results can be obtained from either.
One method consists of removing a half to one inch ring
of bark from the branch. Make one cut through the bark com-
pletely encircling the twig and another cut one-half to one inch
above it. Remove the bark between the two cuts, exposing the
wood. Be sure the cambium layer, a light green area immediately
underneath the bark, is completely removed to prevent new bark
from forming again rather than roots. This method is par-
ticularly adapted when the bark "slips" easily due to the type
of plant or season of the year.
For the second method, make a long slanting cut upward about
one-fourth to one-half way through the twig. On large thick
branches or on branches having brittle wood, a small cut can be
made on either side of the twig. The incision should be kept
open by inserting a small chip of wood, match or toothpick to pre-
vent the cambium layers from uniting and the cut from healing
over.
The use of hormones, growth-producing substances, or root-
inducing compounds is optional. It may hasten rooting on some
hard-to-root materials, but usually does not produce any more
or healthier roots than an untreated layer. These materials
are not substitutes for good care in selecting proper wood or the
correct procedure in making and caring for the layer while it is
rooting.
After making the cut or removing the bark, enclose the injured
area in a ball of moist sphagnum as soon as possible after cutting
to prevent drying out. All excessive moisture should be squeezed
out of the ball by hand before applying it to the cut surface. It
should then contain the proper amount of moisture. The ball
is constructed by taking two handfuls of sphagnum moss and
placing them over the cut surface. The ball should be firmed
snugly around the twig to insure good contact. This will form
a covering thickest near the center and tapered towards the
ends. Tie the ball firmly in place with strong twine. Enclose
the moss ball with polyethylene film and tie securely above and
below the ball to prevent evaporation of moisture. Rubber bands
are ideal for tying the film, since they will expand with any







growth of the twig, thus preventing girdling and possible failure
of the layer to root.
It is better not to remove the layer for transplanting until at
least five, six or more roots are evident between the ball and
polyethylene film. Where aluminum foil or freezer paper is
used as the wrapping material, it must be removed from time to
time to see if roots have developed. This operation often injures
new roots and is the one drawback to the use of these materials.
When foil is used, drying of the ball is usually faster than when
polyethylene is used. Occasionally, where polyethylene-wrapped
balls are exposed to full sun, it is necessary to cover it with
craft paper to prevent scalding of roots by direct rays of the
sun. Any wrapping material or method which permits balls to
dry out will fail to produce roots.
After the roots have formed-this takes from two weeks to
several months, depending largely on season and the type and
vigor or condition of the plant-the layer can be severed from
the parent just below the ball of moss and roots. The film must
be removed before planting, but the ball of mess should not
be disturbed. Attempts at removing the moss ball usually re-
sult in breaking or otherwise injuring the newly-formed roots.
Once the layer has been removed it should be handled carefully
in planting. If the ball of moss is dry moisten it good. It is
important that the roots be kept moist during any planting or
transplanting operations.
The amateur will find it advantageous if he removes a major
portion of the leaves when he sets the newly rooted layer in
the garden. This enables the new plant to become established
more rapidly. A large leaf area will transpire generous amounts
of water, and when the layer is severed from the parent plant
it sometimes does not have sufficient roots to supply the needs
of the top, which can result in eventual death of the layer.
Therefore. removal of some of the leaves is advisable for the
home gardener.
When separating and transplanting other types of layers where
a ball of moss is not used in the propagative process, be sure to
keep the roots moist during the transplanting operation by
wrapping them in moist burlap, paper or other material.
The new layer or plant is then ready for potting or setting
in the field. It is best for the new plant to develop a larger
root system before planting in open areas where high light
intensities and drier conditions usually prevail. Since they re-
quire extra attention immediately after being severed from the






mother plant, potting is suggested as an easy method of handling
these plants. After further root development in the pot, the
plants are better able to withstand field conditions. Some of
the Florida plants commonly propagated by air layering are
Fiddle-Leaf fig, rubber plant, Crotons, Hibiscus, Calliandra,
Oleander, Pandanus, Camellia and Azaleas.

Tip Layering
Most plants with drooping or "viny" growth habits can be
propagated easily by tip layering (Fig. 2). Like air layering,
this is another popular method of plant propagation among home-
owners.










_5


Fig. 2.-TIP LAYERING-An easy method of propagating plants around
the home.

A low branch, or one which can be bent easily to the ground,
is chosen. About 6 to 18 inches back from the tip, the bark is
injured, either by ringing or by a slicing cut as described under
air layering, or by merely scraping the bark from a small area
to stop or restrict food movement down from the leaves, causing
a buildup of food at the point buried to hasten rooting. The
injured area of the bark is anchored in the soil deep enough to
remain moist. It is advantageous to add peat to the soil that
will be used for covering, plus mulch to help keep the area moist.
It is of utmost importance to keep the soil moist. The leafy tip
of the branch is left above ground.
Spring is the best time to tip layer plants, since the injured
portion will develop roots during the summer months and can
either be cut from the parent in late fall and set out or left
until time for spring growth to begin and then severed and
planted. It is a good idea to check the layered portion for roots
5






before severing it from the parent plant. Climbing roses,
January Jasmine, Abelia, Oleander and Pyracantha can be propa-
gated by tip layers.

Trench Layering
This method of asexual propagation is especially adapted for
deciduous fruit crops as pears, grapes and blackberries. It is an
adaptation of the tip layering method.












Fig. 3.-TRENCH LAYERING-This method is well adapted to the
propagation of certain fruit and berry plants.

Trench layering (Fig. 3) is usually practiced in midsummer.
Branches of current season growth which can be readily bent to
the ground close to the plant are chosen and all the leaves except
at the tip of the limb and lateral branches are removed. Prune
the lateral, where present, back to two or three buds. The limb
is then placed in a small trench and then when the buds break,
all but the tip of the main lamb and laterals should be covered
with about four to six inches of soil. Since buds on most plants
will not develop when buried, this method should not be used
except for those plants recommended above.
Roots will form at each node and a new plant will develop.
Rooting can be hastened by making a shallow cut below each
bud. The length of time required for rooting will vary with the
plant material, temperature and moisture conditions. As soon
as the roots develop and the buds begin to elongate the layer
can be severed from the parent plant and potted or transplanted.
Some growers propagate Willows, Viburnum and Dogwood by
trench layering.
Mound Layering
This method is used to propagate many of the heavy-stemmed
or closely-branched plants. It is also used when it is desirable
6







to root all the branches of plants like Japanese magnolia, or to
multiply tender shrubs that have been severely injured by the
cold, which necessitates cutting back close to the ground.
















Fig. 4.-MOUND LAYERING-Showing roots forming in the soil mounded
around the wounded stems.

Mound layering (Fig. 4) may be done in the spring. In
general, it is best to cut the plant back severely the previous
season to force new shoots close to the ground and in the center
of the plant. The shoots can be injured, as previously mentioned
in tip layering, or by chopping through the clump with a potato
fork or similar tined implement near the soil surface. The soil
is then mounted up around the base of the plant. The mounding
soil should contain peat or sphagnum moss for ease in removing
the rooted branches. It takes about one growing season to pro-
duce a twig that is sufficiently rooted for transplanting. Rooted
twigs can be set out in late fall or early spring. Besides the
Japanese magnolia, such plants as Crotons, Flowering Quince,
Calliandra and Tibouchina can be propagated by this method.

Serpentine Layering
Serpentine layering (Fig. 5) is best adapted to plants with
pliable canes or ornamental vines. It is a variation of trench
layering in which alternate buds are buried and alternate buds
left above the ground.
Spring is the preferred time of year to start this type of layer-
ing. Any long stem located close to the ground can be used.
The twig is bent down, alternating with one bud below ground

7






and one above ground. Here again it will help to make a shallow
cut below each bud that is buried. The covered portions can
be held in place by using a peg, bent wire or stone. If kept moist,
they will usually root and should be ready for transplanting by
early fall. Grapes, Virginia Creeper, Trumpet Creeper and most
vines can be propagated by serpentine layering.


Fig. 5.-SERPENTINE LAYERING-Alternate nodes along the branch
are rooted, a method of securing a large number of plants from one branch.































COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
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