When to Prune Flowering Ornamental Shrubs and Trees by ...

February 24, 2013
When to Prune Flowering Ornamental Shrubs and Trees

by Annette Meyer Heisdorffer
Daviess County Extension Agent for Horticulture
“When should I prune certain shrubs and trees?” is a common question during the
winter. Woody plants are pruned to correct undesirable growth, to control size and shape,
and to remove damaged and low hanging branches. Pruning time is based on the flowering
period of the shrub or tree.
Shrubs are pruned to encourage flower production every year. If showy fruits are a
feature of the plant you are pruning, remember that the fruits develop from the flowers.
Removing the flowers will also remove the fruit.
Shrubs that flower before the end of May should be pruned during or immediately after
flowering. The flowers are formed on wood from the previous summer. By pruning them
right after they bloom, maximum time is allowed before winter to develop the wood for next
season's show of flowers. If pruned during the winter or before flowering in the spring,
flower buds are removed and blossoms are reduced or eliminated for the coming season.
Examples of early flowering shrubs in this category are as follows: barberries,
flowering quince, cornelian cherry, deutzias, forsythias, hollies, mountain laurel, privets or
ligustrums, honeysuckles, magnolias, mock oranges, firethorns, hawthorns, azaleas and
rhododendrons, black jetbead, thunberg spirea, bridalwreath spirea, Japanese snowball,
common lilac, Chinese lilac, French lilac, and viburnums.
Shrubs that flower after the end of May should be pruned in the winter or spring before

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new growth begins. They bloom on wood formed during the current spring or summer.
Examples of summer flowering shrubs are as follows: five-leaf aralia, glossy abelia,

butterflybush, beautyberry, summersweet clethra, rose of Sharon, hills of snow hydrangea,
peegee hydrangea, oakleaf hydrangea, crape myrtle, and hybrid tea rose.

Certain shrubs may be pruned lightly before and after flowering. This will often
increase flowering and fruit production and may result in a second bloom during the year.
Examples of this group are as follows: glossy abelia, butterflybush, red twig dogwood,
spreading cotoneaster, multiflora cotoneaster, Oregon hollygrape, Anthony waterer spirea,
Frobel spirea, snowberry, and wiegela.

Ornamental trees that flower before the end of May should be pruned immediately after
flowering. These include redbuds, magnolias, flowering dogwoods, hawthorns, crabapples,
flowering cherries, flowering pears, flowering plums, horse chestnuts, buckeyes,
serviceberries, fringetrees, silverbells, witchhazels, hollies, and chestnuts.

Ornamental trees which flower after the end of May should be pruned in winter or
spring before new growth or budbreak begins. These include golden rain tree, mimosa,
Japanese pagodatree, sourwood, and other late-flowering trees.

Some trees, such as birch, yellowwood, elm, pine, spruce, fir, and maple, may bleed
excessively if pruned in the spring. Bleeding or loss of sap will not harm the tree but may be
unsightly or messy around the home. Bleeding may be reduced by pruning such trees when
they are in full leaf (June).

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The worst time to prune is at bud break in the spring. The tree or shrub is using all of
the stored energy from the last season to develop the leaves. At this time the injuries are much
worse.

Proper removal of branches is important. Care should be taken to neither cut too close
nor to leave a stub. Cutting too close removes tissue that signals the plant to set boundaries for
resisting the spread of disease infection. Leaving a stub will inhibit the formation of a
boundary and result in decay spreading from the stub into the tree. For the proper removal of
branches, all cuts should be made back to or just above a growing point. For example, remove
branches just above a bud, above a side branch, back to a main branch or trunk, or back to the
ground.

Remember, your pruning equipment should be sharp because a clean cut heals faster
and causes less injury to the tree. After the branch is removed properly, allow the tree to use
its own defenses and protect itself.

Pruners and pruning saws are tools used to maintain shrubs and trees. The bypass type
of pruning tools have a scissors cutting action that will cleanly cut the stem without crushing it.
Pruning saws are designed to cut on the pull stroke. The blades are narrow to be able to fit
into tight spaces and still make clean cuts.
Hand pruners are best to use to cut stems up to three-quarter inch in diameter. Attempting to
cut larger branches risks making a poor cut and/or ruining the shears. Two-handed lopping
shears can be used to cut branches up to 1 to 1.5 inches in diameter. Pruning

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saws are recommended for removing branches over 1 inch in diameter.
Keep in mind to disinfect pruning tools when pruning a tree with a disease before

pruning a healthy plant or branch. The blades of the tools can be disinfected by applying Lysol
or 70 percent denatured ethyl alcohol to them.

For more information about pruning shrubs and trees, contact the Daviess County
Cooperative Extension Service at 270-685-8480.
Question and Answer:

Should I apply a paint or tar over the area where I removed a branch on a tree? No.
Research has proven that painting a tree wound is not beneficial and may actually do more
harm than good. In some cases, it may increase the amount of internal decay.
Upcoming Event:

The Extension Master Gardeners are sponsoring the presentation “Vertical, Balcony, and
Roof Top Gardens” by guest speaker Tracey Williams at the Daviess County Public Library on
Saturday, March 2, at 11:00 a.m. Call 685-8480 to make reservations for the free event. Seating
is limited.
Educational programs of Kentucky Cooperative Extension serve all people regardless of race,
color, age, sex, religion, disability, or national origin.

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