 |
 |
 |
 |
 |
 |
 |
Pruning
Source: Virginia State University Cooperative Extension
Shrub Pruning Calendar Deciduous Pruning Calendar Evergreen Pruning Calendar Pruning Guide The National Forest: Pruning for Quality
Pruning Basics
Pruning is a regular part of tree maintenance involving the selective removal of shoots
and branches.Why prune?
- To improve the appearance or health of the tree. Prompt removal of
diseased, damaged, or dead plant parts speeds the formation of callus tissue
(i.e., tissue that covers the cut surface or wound), and sometimes limits the
spread of insects and disease. Pruning a dense canopy permits better air
circulation and sunlight penetration.- To control the size of a tree. Pruning can keep the size of a tree in
better proportion with your landscape. It can also decrease shade, prevent
interference with utility lines, and allow better access for pest control.- To prevent personal injury or property damage. Remove dead or hazardously
low limbs to make underlying areas safer. Have trained or certified arborists
handle any pruning work in the crowns of large trees.- To train young plants. Train branches that form the structure of the canopy
to produce stronger and more vigorous trees. You'll find it easier to shape
branches with hand pruners when a plant is young than to prune larger
branches later. Pruning often begins with young plants for bonsai, topiary,
espalier, or other types of special plant training.- To rejuvenate old trees. As trees mature, their forms may become
unattractive. Pruning can restore vigor.- To influence fruiting and flowering. You can also use selective pruning
to stimulate flowering in some species and to help produce larger (though
fewer) fruits in others.
Pruning Tools (See Tools of the Trade)
- Use hand pruners to cut stems up to ¾ inches in diameter.
- Use lopping shears to cut through branches that are up to 1¾ inches in
diameter.- Use pruning saws to remove stems you cannot cut with hand pruners or
lopping shears.
- Use pole pruners to cut out-of-reach branches up to 2 inches in diameter.
- Use chain saws to remove branches greater than 3 inches in diameter.
Chain saws should be used only with appropriate safety gear by people
who fully understand their operation.What to Prune
Trees that shed their leaves annually are classified as deciduous. The above-ground
part of a tree consists of the trunk, scaffold branches, and lateral branches. The
leader is the vertical stem at the top of the trunk. Scaffold branches are primary limbs
that form a tree's canopy. Secondary branches that emerge from scaffold branches
are laterals. Growth comes from buds at the tips of branches (terminal buds),
or along branch sides (lateral buds). Water sprouts and suckers are two types of
vigorous shoot growth generally considered undesirable. Water sprouts occur
along branches, usually at pruning sites. Suckers grow from the trunk or roots.Corrective pruning removes damaged wood and eliminates rubbing branches. When
pruning dead or diseased branches, make cuts into healthy wood, well below the
affected area. Disinfect tools between each cut with products such as "Lysol,"
"Listerine," or rubbing alcohol; "Pine-Sol" and household bleach are highly corrosive
to metal tools. Remove rubbing or poorly placed branches as early as possible.
Water sprouts and suckers always interfere with normal growth, so prune them
off completely as they appear.Young tree pruning can eliminate potential problems before they occur. Select
permanent scaffold branches with wide angles of attachment to the trunk. Narrow
angles of branch attachment signal a point of future weakness. Be sure branches
are evenly spaced (at least 10 inches-12 inches apart) and arranged radially around
the trunk. Don't allow one limb to remain directly above another limb, shading it out.
Train trees to single leaders and prevent any laterals from growing higher than the
terminal leader, unless multi-stemmed specimens are desired. When a tree's leader
is lost due to storm damage or disease, replace it by splinting an upper lateral
on the highest scaffold to a vertical position; use wood or flexible wire splints,
removing them after one growing season. Prune all laterals immediately below the
new leader.Prune to alter the natural growth habit of trees. For a more open tree, leave terminal
buds on all scaffold branches, but shorten or eliminate all laterals. For a taller tree,
remove all branches up to a height of 8 feet as soon as the tree has three to four
scaffold limbs above this height. For a more compact tree, shorten all scaffold
branches by half, prune above outward-facing buds, and allow most laterals to
develop.How to Prune
There are two basic types of pruning cuts: heading cuts and thinning cuts.Make heading cuts to reduce the height of a tree by cutting back lateral branches
and removing terminal buds. Heading cuts stimulate growth of buds closest to the
cut. The direction in which the top remaining lateral bud is pointing will determine
the direction of new growth. Don't use heading cuts (also called topping) on branches
over one year old, to avoid stimulating unwanted water sprouts and suckers. Heading
or topping also disfigures older trees and exposes large areas of bare wood to disease
and insects. For heading cuts on young branches, cut ¼ inch above a lateral bud,
sloping down and away from the bud. Avoid cutting too close, or steep, or the bud
may die.Thinning cuts remove branches to their points of origin or attachment. When
you prune a branch back to another branch, or prune a branch from the trunk,
you are thinning. Thinning cuts stimulate growth throughout the tree, rather than
in single branches, as do heading cuts. Advantages of thinning include better
air circulation, improved sunlight penetration, and less wind resistance. When
making thinning cuts to larger branches, cut outside the branch collar at a 45 to
60 degree angle to the branch bark ridge. Leave the branch collar intact to help
prevent decay from entering the trunk.The best pruning cut is made outside the branch collar, at a 45 to 60 degree angle
to the branch bark ridge. Leave the branch collar intact to help prevent decay
from entering the trunk. When removing limbs greater than 1 inch in diameter,
use the three-cut method to avoid tearing bark: First, about 12 inches from the
trunk, cut halfway through the limb from the underside. Second, about 1 inch past
the first cut, cut through the limb from the top side. The limb's weight will cause it
to break between the two cuts. Make the third cut outside the branch collar.
Use a handsaw to provide greater control.Don't coat pruning cuts with tree paint or wound dressing.
When to Prune
Pruning at different seasons triggers different responses. Late winter or early spring,
before bud break, is a good time to prune many species because callus tissue forms
rapidly. When pruning flowering trees, take care not to cut off flower buds. Some
trees, such as cherry, plum, and crabapple, form buds on old wood. Others, such
as crape myrtle, bloom on new wood.Summer pruning tends to suppress growth of both suckers and foliage. Late summer
or early fall pruning causes vigorous regrowth, which in some species may not harden
off by winter, leading to possible cold damage. Whenever unexpected damage
from vandalism or bad weather occurs, prune immediately.Deciduous tree pruning calendar:
http://www.ext.vt.edu/pubs/nursery/430-460/ 430-460.htmlPruning Evergreen Trees
Evergreen trees, including most conifers and some broad-leaved trees, have leaves
that persist year round. Evergreen trees generally need less pruning than deciduous
trees. Conifers are distinguished from other plants by their needle or scale-like leaves
and their seed-bearing cones. Because conifers have dominant leaders, young trees
rarely require training-type pruning. The leader is the vertical stem at the top of the
trunk. If a young tree has two leaders, prune one out to prevent multiple
leader development. Selective branch removal is generally unnecessary as evergreens
tend to have wide angles of attachment to the trunk.What to Prune
Corrective pruning for evergreen trees consists mainly of dead, diseased, or
damaged branch removal. Remove dead wood promptly by cutting dead branches
back to healthy branches. When pruning diseased branches, make thinning cuts
into healthy wood well below the infected area. Thinning cuts remove branches to
their points of origin or attachment. Disinfect tools between each cut with products
such as "Lysol," "Listerine," or rubbing alcohol; "Pine-Sol" and household bleach are
highly corrosive to metal tools.Allow evergreen trees to grow in their natural form. Don't prune into the inactive
center (no needles or leaves attached) of whorl-branched conifers because new
branches won't form to conceal the stubs. When a tree's leader is lost due to
storm damage or disease, replace it by splinting to a vertical position the upper
lateral on the highest branch; use wood or flexible wire splints, removing them after
one growing season. Prune all laterals immediately below the new leader.How to Prune
The best pruning cut is made outside the branch collar, at a 45 to 60 degree angle
to the branch bark ridge. Leave the branch collar intact to help prevent decay
from entering the trunk. When removing limbs greater than 1 inch in diameter, use
the three-cut method to avoid tearing bark: First, about 12 inches from the trunk,
cut halfway through the limb from the underside. Second, about 1 inch past the first
cut, cut through the limb from the top side. The limb's weight will cause it to break
between the two cuts. Make the third cut outside the branch collar. Use a handsaw
to provide greater control.Don't coat pruning cuts with tree paint or wound dressing.
Pines and other whorl-branched conifers become denser if new growing tips ("candles")
are pinched in half as they expand in the spring. Pinch by hand, as pruning shears will
cut the expanding needles and leave them with brown tips.When to Prune
Most evergreen pruning is done for corrective reasons, so seasonal timing is not
as important as it is for deciduous species. Pruning during dormancy is the most
common practice and will result in a vigorous burst of spring growth. Whenever
unexpected damage from vandalism or bad weather occurs, prune immediately.There are, however, certain evergreen pruning activities for specific times of the
year. Prune random-branched conifers in early spring when new growth will cover
the pruning wounds. "Candles" of whorl-branched conifers must be pinched back in
mid to late spring. Maintenance pruning of random-branched conifers is done in summer
to keep plants within a desired size range. Remove spent flowers of evergreen magnolias
at the end of their blooming season to stimulate new growth and development of a
thicker crown. During the Christmas season, minor pruning for decorative purposes
usually causes no harm.Whenever possible, avoid pruning evergreen trees in late summer and early fall.
Pruning at this time can stimulate new growth that may not harden off before winter,
and thus may be damaged or killed by the cold.Evergreen tree pruning calendar:
http://www.ext.vt.edu/pubs/nursery/430-461/430-461.htmlPruning Basics
Pruning is a regular part of shrub maintenance involving the selective removal of
shoots and branches.Why prune?
- To improve the appearance or health of the plant. Prompt removal of
diseased, damaged, or dead plant parts speeds the formation of callus tissue
(i.e., tissue that covers the cut surface or wound), and sometimes limits the
spread of insects and disease.- To control the size of a plant. Pruning can keep the size of a plant in
better proportion with your landscape.- To train young plants. Pruning often begins with young plants for bonsai,
topiary, espalier, or other types of special plant training.- To rejuvenate old trees. As trees mature, their forms may become
unattractive. Pruning can restore vigor.- To influence fruiting and flowering. Proper pruning of flower buds encourages
early vegetative growth. You can also use selective pruning to stimulate
flowering in some species and to help produce larger (though fewer) fruits in
others.Pruning Tools (See Tools of the Trade)
- Use hand pruners to cut stems up to ¾ inches in diameter.
- Use lopping shears to cut through branches that are up to 1 ¾ inches in
diameter.- Use pruning saws to remove stems you cannot cut with hand pruners or
lopping shears.- Use pole pruners to cut out-of-reach branches up to 2 inches in diameter.
- Use chain saws to remove branches greater than 3 inches in diameter.
- Use hedge clippers or pruning shears to trim thin-stemmed hedges. If
you have a long hedge, you may have to use hedge clippers when hand
pruning is impractical. With repeated shearing, hedges develop a profusion
of outer twigs, die back in the center, and often show an increase in pest
problems.Shrub Growth Habit
The natural "habit" or shape of a shrub will dictate how to prune them. All shoots
grow outward from their tips and whenever tips are removed lower buds are stimulated
to grow. Buds are located at nodes, where leaves are attached to twigs and
branches. Each node produces from one to three buds, depending on the species.Shrubs have mounding, cane, or tree-like growth habits. Those with mounding
habits, such as evergreen azalea and spirea, generally have soft, flexible stems,
small leaves, and are often used in mass plantings. Shrubs with cane habits, such
as forsythia, spread by sending up erect new branches, the canes, from their base.
Tree-like shrubs have woodier, finely divided branches; witch hazel and rhododendron
are examples of such shrubs.How to Prune
There are two basic types of pruning cuts: heading cuts and thinning cuts. Heading
cuts stimulate growth of buds closest to the wound; the direction in which the
top remaining bud is pointing will determine the direction of new growth.Make heading cuts selectively to reduce shrub height and retain natural form.
Non-selective heading cuts made indiscriminately will stimulate rapid regrowth
from buds below the cut. These vigorous shoots are unattractive and make shrubs
bushier, but
not smaller. Non-selective heading cuts are only justifiable when using hedge
clippers on a hedge or topiaried shrub. For heading cuts, prune ¼ inch above the
bud, sloping down and away from it. Avoid cutting too close, or steep, or the bud
may die. When pruning above a node with two or more buds, remove the inward-
facing ones. Make thinning cuts just above parent or side branches and roughly
parallel to them.Thinning cuts remove branches at their points of origin or attachment. Used in
moderation, thinning cuts reduce shrub density without stimulating regrowth.
Make thinning cuts just above parent or side branches and roughly parallel to them.Maintenance Pruning
Deciduous shrubs require maintenance pruning to keep them healthy and in scale
with their surroundings. Maintenance pruning practices should begin at the time of
planting or after rejuvenation of older shrubs. Disinfect tools between each cut
with products such as "Lysol," "Listerine," or rubbing alcohol; "Pine-Sol" and
household bleach are highly corrosive to metal tools.Always remove dead, diseased, or broken branches promptly. When pruning
dead or diseased branches, make thinning cuts into healthy wood, well below the
affected area. To reduce the height of shrubs with a cane habit, first remove the
tallest canes by cutting or sawing them out near ground level. Then, thin out any
canes crowding the center, as well as those growing in an unwanted or unruly
direction.For height maintenance of mounding-type shrubs, prune only the longest branches.
Make thinning cuts well inside the shrub mass where they won't be visible.
This method reduces mounding shrubs by up to one-third their size without
sacrificing their shape.Shrubs with a tree-like habit are the most difficult to shorten. After removing any
rubbing branches, prune to open up the center of the shrub. Keep the crown open
and maximize light penetration by careful use of thinning cuts. Prune branches that
touch the ground and suckers originating from the roots. Wait until the very end of
the job to make any heading cuts. Tree-like shrubs can usually tolerate removal of
one-eighth to one-fourth of their branches.Rejuvenation Pruning
Older shrubs often grow out of proportion with their surroundings and may have
large amounts of unproductive wood. Keep the following in mind with rejuvenation
pruning:
- Select an appropriate species; not all shrubs respond well to drastic pruning.
- Observe proper timing; the preferred time for renovative pruning is just before
bud break in early spring.- Give extra care to heavily pruned shrubs; fertilization, watering, and pest control
will be critical factors.- Consider the shrub's new appearance; what will be the immediate impact
on the landscape?Two techniques are used to restore old shrubs, provided they still have sufficient
vigor and are growing in a favorable location:
- The first technique involves complete removal of the entire plant 6-10 inches
above the ground. Use heavy lopping shears and a pruning saw. Remove half
of the new canes that develop by mid- summer, and head back some of
the remaining canes. When using a heading cut, be sure to prune to outward-
pointing buds so that the inner portion does not become too dense. Shrubs
that tolerate extensive rejuvenation are: abelia, dogwood, honeysuckle,
hydrangea, lilac, mallow, rose-of-Sharon, spirea, and St. John's wort
(hypericum).- The second technique removes growth more gradually. The first year, remove
one-third of the oldest, unproductive branches. The next year, take one-half
of the old, lingering stems. Finally, in the third year, prune out the remainder of
the old branches. New, productive stems should quickly replace the old wood.
This method takes longer to complete but the shrub stays more
attractive throughout the rejuvenation period.When to Prune
Pruning at different seasons triggers different responses. Late winter or early
spring, before bud break, is usually the best time to prune many species because
new tissue forms rapidly. However, pruning should be delayed for most spring-
blooming shrubs until immediately after flowering to avoid reducing the floral
display. Summer pruning tends to suppress growth of both suckers and foliage.
Summer- blooming shrubs should be pruned in early spring prior to bud set or in
summer immediately following flowering. Late summer or early fall pruning causes
vigorous regrowth which in some cases may not harden off by winter, leading to
possible cold damage. Whenever unexpected damage from vandalism or bad
weather occurs, prune at once.Shrub pruning calendar: http://www.ext.vt.edu/pubs/nursery/430-462/430-462.html
