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University
of Rhode Island GreenShare Factsheets
Pruning
Deciduous Shrubs
Deciduous shrubs are woody plants that drop their leaves
in autumn. Examples of deciduous shrubs are lilac, forsythia,
snowball viburnum, and cranberry cotoneaster. Deciduous shrubs
are valued in the landscape for their foliage, branching characteristics,
fall leaf color, flowers or colored twigs in winter. Some shrubs
have colorful fruit that attracts birds. Selection of deciduous
shrubs should be based on their function in the landscape. Shrubs
have different habits of growth, fast, medium or slow, with upright,
wide-spreading, arching or horizontal branching. The proper selection
of the right plant for height and spread at maturity can reduce
the need for pruning.
Before you start to prune, know what you wish to accomplish.
Pruning is one of the essential but least understood of the garden
maintenance practices. Good pruning is the selective removal
of branches without changing the plant's natural appearance or
habit of growth. Shrubs trimmed to an artificial size or shape
require more pruning than shrubs pruned to keep their natural
shape. Prune to improve the health of the shrub by cutting out
dead, diseased, broken and overgrown branches that interfere
with new growth. Prune to control the shrub's size, shape, flower,
fruit and colored twig effect.
Three methods used to prune a shrub
for a specific purpose are thinning-out, renewal or rejuvenation
and heading back or
shearing. By thinning out, a branch or twig is cut off at its
point of origin from the parent stem, to a lateral side branch,
to a "Y" of a branch junction or at the ground level. This method
of pruning results in a more open plant and does not stimulate
excessive new growth. Considerable growth can be cut off without
changing the plant's natural appearance or habit of growth. Plants
can be maintained at a given height and spread for years by thinning
out. This method of pruning is best done with hand pruning shears,
not hedge shears. Thinning allows room for growth of side branches.
Thin out the oldest and tallest stems first.
By renewal pruning, the oldest branches are gradually removed
from an overgrown shrub at the ground level. It is best to do
this over a three-year or longer period, leaving the younger
more vigorous branches. New shoots that develop can be cut back
to various lengths by the thinning method to develop into strong
branches.
Heading back or shearing refers to cutting back a branch
anywhere along the length of a stem. The cut may be above a bud,
below a bud, or it may even leave a stub. The effect of heading
back or shearing is to concentrate vigorous upright new growth
below the cut. This method of pruning is frequently done with
hedge shears without regard for the natural form or branching
of the plants. If every branch or twig is headed back, more growth
develops than was removed by the pruning. The natural form of
the plant is altered by the extra growth. Hedges are pruned to
a definite size or shape with hedge shears.
Avoid leaving stubs when pruning even a small shoot or twig.
Short stubs will not heal over properly and will eventually provide
a source of entry for insects and diseases. Cuts too far above
a bud may destroy the bud by decay or die-back. Cuts too close
to the bud may dry out the bud, especially in winter. The proper
pruning cut should be 1/8 to 3/8 of an inch above the bud, slightly
slanted away from the bud.
The ideal time to prune most plants is during the dormant
season prior to the start of new growth. Flowering shrubs may
be an exception. Shrubs that bloom in spring may be pruned after
flowering. Late flowering shrubs that bloom on wood produced
the same year can be pruned before growth starts in the spring.
Some landscape horticulturists believe the effect of the
shrub's structural branching characteristics is more important
than its flowering effect in the total landscape design. Therefore,
it may be better to prune all flowering shrubs in early spring
before new growth starts. Some bloom will be sacrificed by this
method. Either method can be recommended. One has to determine
for himself the time to prune deciduous shrubs.
Pruning shears -- for branches 1/2 to 3/4 inches
in diameter. Twisting shears to cut larger branches will strain
and weaken them. The anvil-type of pruning shears is satisfactory
for general pruning. However, the scissors or draw-cut type hand
shear is preferred for close-cut precision pruning. Lopping
shears -- have long handles and are designed to cut larger
branches 3/4 to 2 inches in diameter. Pruning saws --
have narrow blades, coarse teeth and are designed to cut on the
pull stroke. Small curved pruning saws are useful to prune larger
shrubs. Hedge shears -- are used for shearing hedges or
formal-shaped plants. Avoid using hedge shears for other pruning
purposes.
Adapted from Fred K. Buscher,
Ohio State University, 2000
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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