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PRUNING, SHEARING AND REJUVENATING PLANTS
Presented by
Eric M. Wenger, President
Complete Plant Health Care, Inc.
Lawn and Garden Hotline: 301-590-9650
Email: mgmont@umd.edu
Website: www.mcmg.umd.edu
Website: www.hgic.umd.edu
Don't Let
Pruning Be
Confusing
Pruning
Why prune or shear plants?
What is the difference between pruning and
shearing?
What tools are needed?
How and when to prune and shear.
When do I need a professional?
Why Prune or Shear Plants?
Pruning and shearing are techniques used to
enhance the health and appearance of plants, such
as removal of dead or diseased wood.
These techniques, when done properly, also increase
and improve the production of fruit and flowers.
Pruning and shearing are also used to control or
direct growth and can be used to control the
temperature, light and air movement of a landscape.
Why Prune & Shear Plants?
What Is the Difference Between Pruning and Shearing?
Both pruning and shearing can be used to shape plants.
Pruning is usually very specific and can be used to dwarf a plant
or make it taller.
Heading is a type of pruning used to reduce a plant’s size and
make it thicker.
Thinning is designed to help air movement and to create a more
open natural looking plant.
Shearing is generally used to create a more dense and formal
plant, such as for screens, hedges, topiary and borders.
What Tools Are Needed?
The avid gardener will have an assortment of high quality tools.
Remember, you get what you pay for. A cheap pruning tool will probably not cut very well or last very long. A quality tool will last a lifetime if properly cared for and is a good investment.
A basic assortment of pruning tools would consist of a hand pruner, loppers, 6”- 10” handsaw, and manual hedge shears. Bypass or scissor action hand pruners and loppers are superior to the anvil cut type.
What Tools are Needed?
To have one complete set of tools, one can add a
pruning knife, bow saw, pole pruner, gasoline or
electric hedge shears, and a chainsaw (gas or
electric).
Remember, that electric tools are lighter than gas but
not as powerful. Also, there is the cord to deal with.
Gas tools are more powerful and give more freedom
of movement but are heavier and you must deal with
gas and oil.
What Tools are Needed?
Of course all tools have the potential to cause a great
deal of physical harm and should be treated with care
and respect.
Always read the owners/operators manual and follow
all safety precautions.
It is always a good idea to have and use safety
glasses, gloves and hearing protection.
How and When to Prune and Shear
Although there are thousands of different types of trees and shrubs, there are only a few basic principles of pruning.
The principles are applied to each type of plant according to its needs.
Timing can be extremely important to insure proper results, although there is no “exact” time of year to prune any tree or shrub.
Knowing the type of plant you are going to prune or shear is all-important, such as whether the plant flowers on old or new wood.
When to Prune …
A general seasonal guide would be as follows:
Late winter and early spring:
Remove old canes from mature shrubs, except those that flower in the spring.
Prune deciduous hedges, dormant fruit trees, grape vines, blueberries and brambles.
Prune branches that are too low and any crossing branches on flowering ornamental trees.
Late spring to early summer:
Remove old canes on mature shrubs after bloom.
Pinch new growth on evergreens.
Pinch new growth on flowering Azaleas and Rhododendrons.
When to Prune, continued
Throughout summer:
Shear hedges.
Remove lower branches from young shade trees.
Prune evergreen shrubs.
Pinch tips to control growth.
Fall to winter:
Ease off pruning of evergreens.
Prune shade trees.
General Guidelines These rules are general and can be
strayed from or altered as needed, as long as common sense is used.
Natural target pruning is used for trees and is the best way to insure a pruned tree will seal properly.
Natural target pruning is a pruning procedure developed by Dr. Alex Shigo based on our new knowledge of tree and branch growth.
The branch collar or swelling at the base of the branch is identified and a pruning cut is made outside that collar.
If the collar is hard to find, the branch bark ridge (BBR) can be used to determine the proper position for the pruning cut.
The cut is made at an angle equal to the angel between the BBR and a plum line dropped straight from the top of the BBR. The pruning cut should begin outside the BBR.
General Guidelines, continued
Most limbs should be pruned using three (3) cuts.
The first cut is a small undercut to prevent the tree bark from stripping down the trunk.
The next cut is made beyond the first cut to remove most of the weight of the limb.
The third cut is made just outside the branch collar.
There is no need to apply wound dressing or tree paint to the cut surface. However, make sure that no ragged edges or twigs remain attached to the tree.
When trees are pruned using the natural target pruning method, cuts are not flush against the trunk.
Shrubs are pruned by either heading or thinning.
General Guidelines, continued
Thinning consists of cutting out selected branches back to a lateral branch, a lateral bud, or the main trunk.
Thinning can be superior to shearing because thinning creates a full plant by allowing growth within the interior portions of the shrub.
Thinning is more time consuming but must be
used on some plants, such as boxwoods.
General Guidelines, continued
Pruning Guidelines, continued
Prune Dead, Weak, and Crossing Branches
Pruning Guidelines, continued
Pruning Guidelines, continued
Category 1: Shrubs That Bloom on Last Season’s Growth. Prune
After Flowering:
Cercis Chinensis Chinese redbud
Chaenomeles japonica Japanese quince
Chomanthos virginicus Fringe tree
Deutzia spp Spring flowering deutzias
Exochoroa racemosa Pearlbush
Forsythia spp Forsythia species
Kerria japonica Kerria
Lonicera spp Honeysuckle
Magnolia stellata Star magnolia
Philadelphus spp Mockorange species
Pieris spp All species
Rhododendron Azalaea rhododendrons
Rosa spp Rambling rose species
Spiraea spp Early white spirea species
Syringa spp Lilac species
Tamarix parviflora Small flowered tamarix
Viburnum spp Viburnum species
Weigela Florida Old fashioned weigela
Category 2: Shrubs That Bloom on Current Seasons Growth. Prune
in Late Winter to Early Spring.
Abelia x grandiflora Glossy abelia
Buddleia davidii Butterfly bush
Callicarpa japonica Japanese beauty bush
Caryopteris x clandonensis Bluebeard
Clethra alnifolia Summersweet
Hibiscus syriacus Shrub althea
Hydrangea arborescens Hills of Snow hydrangea
Hydrangea paniculata Peegee hydrangea
Hypericum spp St. John’s Wort
Lagerstroemia indica Crape Myrtle
Rosa Sp Bush rose
Spiraea bumalda Anthony waterer spirea
Spireae janical Mikado Spirea
Symphoricarpos spp Coralberry and snowberry
Vitex agnus-castus Chaste Tree
Pruning Guidelines
Many overgrown or out of control shrubs can be
renewed by cutting them down to 8-12 inches high,
although any flowers would be sacrificed for that
year.
This type of cutting back or stooling should be done
early in the year, around March or April.
When pruning twigs and small branches, always cut
back to a vigorous bud or an intersecting branch.
Branches ¾ inch thick and bigger should be cut with
a pruning saw and not loppers.
PLANTS THAT ARE GOOD CANDIDATES FOR RENEWAL PRUNING
Abelia (All Types)
Azalea/Rhododendron (Consider Flowering and Recovery Time)
Barberry (All Types)
Bayberry
Boxwood (English Boxwood Recovers More Slowly Than Most Other
Types)
Buddleia
Cherry Laurel
Crape Myrtle
Euonymus (All Types)
Forsythia
Holly (All Types)
Osmanthus
Nandina (All Types)
Spirea
Yew
Many Others; If You Aren’t Sure, Find Out Before You Prune!
A Rejuvenated Garden Can
Look Like A Brand New
Landscape Without The
Expense Of A New Landscape
Pruning Guidelines
Pruning Evergreen Shrubs
Pruning Evergreen Shrubs
Does the plant have
ornamental flowers?
Does it have ornamental
fruit?
Is it fully hardy in the mid-
Atlantic?
Does it have any significant
pest problems?
Boxwood-Buxus
English Boxwood Korean Boxwood
Korean Boxwood (Buxus microphylla) is similar in
appearance to Japanese holly and is faster growing than
English boxwood.
Boxwood-Buxus
American boxwood (Buxus sempervirens) is a slow
growing evergreen. The cultivar ‘Suffruticosa’ (English
Boxwood) is very slow growing, having a dense,
compact growth habit.
Boxwood-Buxus
Prune: English
boxwood will need to be
thinned occasionally.
Remove dead and inner
branches to allow for
light and air penetration.
Prune: Plants can be
pruned back hard in
spring before new
growth occurs to reduce
plants if needed. Re-
growth will be slow.
Heavenly Bamboo – Nandina domestica
Does not require a lot of
pruning. Pruning off
any spring growth will
eliminate berries in fall.
Dieback from winter
damage may need to be
removed.
Heavenly Bamboo – Nandina domestica
Nandina can be cut completely to the
ground if needed to rejuvenate or if
damaged by cold winter. Plants will not
flower or display fruit until the following
year.
Dwarf Nandina require little or now
pruning. Most cultivars do not display
flower or fruit.
Taxus When is the best time to
cut back Yews?
How should they be
pruned?
Rejuvenation Pruning of Taxus Taxus can be pruned
hard in the dormant
season to lower or bring
back off walks and
buildings. Plants will fill
in, in one to two years.
Bayberry – Myrica pennsylvanica
Prune: Bayberry is an
aggressively growing shrub that
can be heavily pruned if needed.
Best to do in late winter. Easily
rejuvenated or thinned to keep at
appropriate height.
Southern Bayberry-Myrica cerifera
Bayberry cut back in
dormant season and
same plant 1 year later.
Inkberry Holly-Ilex glabra
Native shrub that prefers a soil that is constantly moist and does not dry out. Native species can get quite large while dwarf varieties will usually stay under 5 feet in height. Plants tend to get „leggy‟ especially if allowed to dry out.
Inkberry Holly-Ilex glabra
Shrubs can be pruned back in
dormant season to force out
new growth.
Japanese Holly-Ilex crenata
Plant are often
sheared, creating a
dense canopy.
Increase in pests
(southern red mites)
when excessively
sheared.
Hardiness can be a
problem when first
installed or in
extremely cold
winters.
Japanese Holly-Ilex crenata
Prune; Plants can be cut
back in late winter/early
spring to reduce height.
Thin plants anytime in
dormant season to reduce
effect of shearing and to
increase growth on inside
portion of plant
Japanese Holly-Ilex crenata REJUVENATION PRUNING
Japanese Holly that is dormant
pruned to reduce size and 1
year later.
Chinese Holly-Ilex cornuta
Chinese Holly can
be severely pruned
in late winter or
before growth
starts in spring.
Osmanthus
Osmanthus can be
pruned hard in early
spring if needed.
Injury may occur if
pruned hard in early
winter
Glossy Abelia
Easy plant to grow
in most landscape.
Plants can grow up
to 6 feet, dwarf
cultivars are about
half that size.
May lose leaves
during cold winters.
Glossy Abelia Abelia bloom on NEW
WOOD. Plants can be cut
to the ground in the
dormant season if needed.
Prune back each year to
encourage new growth
and flowering. Light
tipping only in summer.
Aucuba-Aucuba japonica Plants can be pruned
back in late winter or
early spring to manage
height or remove winter
damage.
Redtip Photinia Plants can be pruned hard in
early spring to reduce in size and encourage new „red‟ growth. Leaf spot disease more prevalent when frequently pruned.
Plants can also be pruned into a small tree-like form.
Azalea Azalea are best
pruned when
flowering is done
in late
spring/early
summer, but
before growth
begins.
May, June, July
Pruning Azaleas
Euonymus Euonymus can
be pruned in late winter or early spring to reduce size or open plants up. This will help manage euonymus scale
Juniper
Junipers can be pruned
almost anytime of the
year. Best time is in
dormant season.
Cannot prune into dead
wood.
Leatherleaf Viburnum Leatherleaf Viburnum is
a large growing shrub and will need to be pruned unless given ample room to grow.
Mahonia Shrub can be selectively
pruned if needed to
manage the height or
control legginess.
Japanese Pieris Japanese Pieris do not
like or need much pruning. Remove dead inner branches and selectively remove selected branches if needed. Removing old flowers in late spring can enhance appearance.
Rhododendron Shrubs are best pruned
right after flowering. May take 2-3 years for full recovery if pruning into older wood. Remove old flowers when done flowering.
Removing spent flowers
will increase flowering in
the following year
Berberis julianae – Wintergreen Barberry
Plant will look scraggly if not
pruned. Can be pruned back
hard in dormant season if
needed. Deciduous Barberry
can also be pruned back hard
when needed.
Cherry Laurel Spring flowering shrub.
Does not like to be sheared. Selectively prune out stems to open plant up and to reduce or maintain size
The key to a long lived healthy plant
Mugo Pine – Pinus mugo
Prune:
The new “candles” can be cut
back by 50% in late spring to
keep plants compact. This can
be done with shears if needed.
If individual branches need to
be removed, prune back to a
major limb since plants do not
have buds, other than on their
tips.
Rose Pruning Guidelines
Roses are of great interest to many people and are categorized as a type of specialty pruning.
The basic technique for rose pruning as with other plants is to cut ¼ inch above the nearest outward-facing bud with the cut at 45-
degree angle (the higher point above the bud). Floribundas are usually not pruned as severely as hybrid teas.
Even so, be sure to remove any dead, broken, damaged or blotched branches back to where the pith, or center of the cane, is white and healthy looking.
Next, remove weak, spindly canes, canes growing toward the center of the bush, the weaker of the two canes that crisscross, canes that grow out, then up, and suckers.
Finally trim all remaining canes back to one half of their former height.
Pruning Roses, continued
To prune hybrid teas and grandiflora roses, follow the same principles as described for floribundas, including:
High pruning for more flowers earlier to low pruning for fewer, bigger flowers later;
Pruning to remove weak and crisscrossing canes;
Removing growth an inch below a canker;
Removing of damaged, dead or broken canes back to healthy growth; and
Removing sucker growth as close as possible to the main root.
Reviving Old Neglected Roses
Contrary to popular belief, roses are very
tough.
On farms that have been abandoned for 50
years, sometimes the only plants found still
growing will be asparagus and roses.
The roses will probably be old varieties,
rambler or shrub, but many of the newer
hybrid tea roses also sink deep enough
taproots to last many years.
Reviving Roses, continued
What is the first step in pruning an old, neglected rose? Q
Remove all broken, dead, and diseased parts.
Then prune away all weak, twiggy and inward-growing wood, and wood that is rubbing up against another branch.
Open the center of the bush by pruning to vigorous outward-facing buds.
Cut back young wood to 2 to 3 buds.
Fertilize and spray for fungus and insects.
That’s about all you should do the first year; to do more might send the plant into shock.
Reviving Roses, continued
During the following dormant period, cut out an old branch at ground level.
Reduce one of the remaining old branches by half and cut back two-thirds – not just one-third – of the new wood.
Repeat this the next winter and the third winter as well, if necessary.
You should end up with a rose bush that has no wood over three years old.
Each year during revival pruning, you should see an increase in new wood and better quality roses. If not, you’d better dig up the old rose and replace it with a promising new one.
Not everyone is Qualified to Prune Trees
When Do I Need a Professional? Many large trees, trees that
hang over houses or grow through power lines should be pruned by licensed professionals only.
Pruning trees through power lines can cause serious injury and/or death.
This is no joke and should be taken seriously. Saving a few hundred dollars to risk your life is not a good trade off.
Bibliography
University of Delaware Cooperative Extension Service, Susan Barton, Extension Specialist
University of Maryland Cooperative Extension Service, Professor Steve Dubik, Extension Specialist
University of Maryland HGIC Mimeo # HG84
All About Pruning Ortho Books, 1978, Chevron Chemical Company
Dr. Alex Shigo
Dr. Frank Gouin
Steve Sullivan - Brickman Group
Pictures And Information Supplied By:
Fine Gardening – By Charles W.G.
Smith
Steve Sullivan – The Brickman Group
Dividing Perennials – Mike Maddox
Rock County University of Wisconsin
Extension
University of Illinois Extension
University of Maryland Extension
Montgomery County Master Gardeners
Jake Powell – Technical Support
Questions?
Lawn and Garden Hotline: 301-590-9650
Email: mgmont@umd.edu
Website: www.mcmg.umd.edu
Website: www.hgic.umd.edu
This program was brought to you by
The Master Gardeners Program of
Montgomery County
University of Maryland Extension
College of
Agriculture and Natural Resources
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