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

Good

Candidates

For Renewal

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