Pruning. Pruning: What is it? 2/21/2013. What is Pruning? Pruning is the removal of: What do YOU think?

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Pruning

presentation and activities prepared by Andrea Burke

Cornell University Department of Horticulture

Pruning: What is it?

What do YOU think?

 Pruning is the removal of:

• A) flowers past their prime

• B) dead, broken, or diseased branches on a tree

• C) roots in a potted plant overgrowing their pot

• D) branches on a shrub that are crossing and chafing

• E) A, B, C, and D

• F) just B and D

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What is Pruning?

 Pruning is the removal of:

• A) flowers past their prime

• B) dead, broken, or diseased branches on a tree

• C) roots in a potted plant overgrowing their pot

• D) branches on a shrub that are crossing and chafing

• E) A, B, C, and D

• F) just B and D

 If you guessed E, Congratulations, you’re smarter than a 5th_grader!

What is Pruning?

 Selective removal or reduction of certain plant parts that are not required, are no longer effective, or are of no use to the plant in order to improve the health, value, or beauty of the plant.

 Although shoots and branches are the main targets for removal, roots, flower buds, fruits and seed pods may also be pruned.

Who Can Prune?

 Anyone you trust with scissors and sharp objects can prune trees and shrubs

 Even small children

can help “prune” (AKA deadhead) gone-by flowers in the garden

 If you have ever mowed your lawn, you have already “pruned” the grass!

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Is Pruning Necessary?

 Some species require pruning no matter where they are for optimum flowering, growth, or fruiting.

 Choosing the proper plant for a location will minimize the amount of pruning needed.

• Always read the tag before you

buy the plant at a nursery.

Image from Purdue Cooperative Extension, http://www.ces.purdue.edu/vanderburgh/horticulture/weird/9ftclearance.htm

Pruning: Why Bother?

The Many Reasons Why we Prune

Why do we prune?

 Increase the value and beauty of landscape plants

 Influence fruiting and flowering

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Why do we prune?

 Restrict growth or size of the plant

Images courtesy of Andrea Burke

Before After

Why do we prune?

 To train the plant to grow a certain way

Images courtesy of Matthew Trump and Dake, commons.wikimedia.org

Why do we prune?

 Helps maintain plant health

• Can limit spread of disease

• Removes dead, diseased, or broken branches

• Pruning a dense canopy lets in more air and sunlight  Pruning old trees or shrubs helps rejuvenate them

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Tools of the Trade

Scissors, Saws, and Power Tools

Tools of the Trade

 Hand pruning shears

• For stems up to ¾ inches in diameter

• Bypass pruners

 Scissor type blades that overlap

 More expensive, but make cleaner, closer cuts

• Anvil pruners

 Straight upper blades that cut against flat lower plates

 Usually cheaper, but tend to crush stems as they cut

Images from Virginia Tech Cooperative Extension

Tools of the Trade

 Lopping shears

• Have long handles to give you extra reach and better leverage

• High quality loppers can cut through about 2 or more

inches, depending on the hardness of the wood (oak vs. ash) and condition (live or rotting)

• Ratchet joints and gears assist best in heavy duty jobs

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Tools of the Trade

 Pruning saws

• Useful for cutting larger branches (over 1 inch diameter)

• Fine toothed, curved saws are good for branches up to 2” diameter

• Coarse toothed saws are better for branches 3” or more in diameter

Images from Texas A&M Cooperative Extension

Tools of the Trade

 Hedge shears

• For shearing plants into hedges

• Can be manual or power

• Cut small, succulent stems best

Tools of the Trade

 Pole pruners

• Cutter with one hooked blade above and a cutting blade

beneath, like lopping shears

• Cutter is on a pole and operated by pulling a rope downward

• Cut out of reach branches up to 2” in diameter

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Tools of the Trade

 Chain saws

• Come in a variety of sizes and strengths

• May be gas or electric powered

• For removing branches greater than 3” diameter

• Best for removing trees and cutting firewood

• Always follow safety precautions when using a

chainsaw. The limb you save may be your own.

Caring for your Tools

 Clean and oil tools regularly, including oiling blades and other metal surfaces

 When pruning diseased plants, disinfect shears and blades between cuts with a solution of one part bleach to nine parts water. Oil well at the end of the day to avoid rust.

 Store in a dry room

 Keep cutting edges sharp

 Paint, varnish, or treat wooden handles regularly with linseed oil

 Always use tools properly and follow manufacturer’s

directions

How To Prune

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Before You Cut: Have A Pruning Plan

 Prune first for SAFETY, next for HEALTH, and

finally for AESTHETICS

• Step 1: SAFETY: Dead, broken, or problem limbs

• Step 2: HEALTH: Disease or insect-infested wood

• Step 3: AESTHETICS: Make the tree grow in the

desired shape or fill in gaps

General Guidelines for Making Cuts

 All pruning cuts should be clean and smooth for best healing

• Make sure your tools are sharp!

• Do not leave stubs

• Avoid tearing bark

• Remember – animals wounds heal, plant wounds seal

 Wound dressing is unnecessary

• Sometimes useful to prevent the spread of diseases (oak wilt and Dutch elm disease)

Making Cuts Properly

 Remove as much branch as possible without damaging

the trunk or stem.

 Cut beginning just outside the branch bark ridge, angling down away from the stem of the tree, avoiding the branch collar

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Making Cuts Properly

 Branches big enough to require a saw should be

supported with one hand during cutting

 If the branch is too heavy to support, make a three-step cut to prevent ripping (see diagram)

Image from USDA Forest Service

Pruning Begins at Planting!

 Pruning a tree while it is young is preventative maintenance!

 At planting – remove dead, diseased, or broken branches

 The first winter – begin to train the tree

Pruning Begins at Planting!

 Pruning young shrubs is not as critical as young trees

 Good pruning practices encourage the best branching structure

• For bare root shrubs, thin branches for good spacing

• Prune broken, diseased, or crossing/circular roots

• Newly planted shrubs require little pruning if they were container-grown or dug with a soil ball

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Pruning a Larger Tree

 Most pruning of large trees requires specialized equipment and should be left to qualified, insured professionals

 Consider the natural form of the tree whenever possible

 Three main ways to prune a large tree:

• Crown thinning

• Crown raising

• Crown reduction – least desirable

Crown Thinning

 Selectively remove

branches throughout the crown, focusing on weak branches

 Develops or maintains a

tree’s structure and form

 Promotes better form and

health by increasing light penetration and air movement

 Never remove more than

¼ of the living crown

Crown Raising

 Remove lower branches

to allow more clearance above lawns, sidewalks, streets, etc.

 On younger trees,

maintain temporary branches to encourage taper and protect trees from vandals and sun scald

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Crown Reduction

 Remove large branches at

the top to reduce tree height

 Different from topping, because no stubs are left

 A last resort, as large pruning wounds may lead to decay

 Better long term solution is to plant a shorter tree

Pruning a Larger Tree – Repairing Injury

 Remember: Plant wounds don’t heal, they seal

 Injury to bark

• Cut away damaged bark

• Shape the edge of the wound to an elongated ellipse if possible

• Remove splintered wood and smooth exposed area

with a chisel

Pruning a Larger Tree – Repairing Injury

 Cavities or hollows in the main trunk

• Create weep holes if water is not draining

• Keep the cavity clean of debris and leaves

• It is not necessary to fill the cavity with anything  Storm damage or lightning strike

• Remove broken branches and reshape the tree as much

as possible

• Remove branches shattered or damaged by lightning

• Split crotches or cracked limbs may be mended by

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Pruning Shrubs

 3 main ways:

• Thinning

• Gradual Renewal

• Rejuvenation

Pruning Shrubs - Thinning

 The goal of thinning a shrub is to open the plant and allow in more sunlight and airflow

 Thinning does not stimulate excess new growth, but does open room for side branches to grow

 Cut off branch or twig to its point of origin on the parent branch, to a side branch, or at ground level

 Cut the oldest and tallest stems first (this allows for side branch development)

Pruning Shrubs – Gradual Renewal

 Gradual renewal removes all top-growth over 3 years, encouraging new stems to grow from the roots

• The first year, remove 1/3 of the oldest, thickest branches at or just above ground level

• The second year, remove 1/2 of the remaining old

stems and tip back long shoots growing from the previous pruning cuts

• The third year, remove remaining old wood and tip

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Pruning Shrubs - Rejuvenation

 Rejuvenation involves severely cutting all the branches of a shrub to a set height, usually 6-12” above ground, before new growth begins in the spring

 Rejuvenate every 3-5 years, or when the shrub begins to look excessively leggy

Pruning Shrubs - Rejuvenation

 Some examples of plants that tolerate rejuvenation:

• Rose of sharon, forsythia, privet, honeysuckle, elderberry, spiraea, potentilla, red-twig dogwood, lilac, and most Hydrangea

 Examples of plants that do NOT tolerate rejuvenation:

• Boxwood, juniper, pine, cypress, cedar, arborvitae, yew, and other narrow leaf evergreens

• Shrubs with excessive amounts of dead branches

(more than 1/3)

Pruning Shrubs

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Pruning Hedges

 Prune hedges often, approximately after every 6 to 8 inches of growth, to within 2 inches of the last pruning

 Prune up to twice a year, in the spring and again in mid-summer

 Ideally, the hedge should be wider at the base than at the top, to allow equal access to sunlight and prevent legginess

Pruning Hedges Can Be Fun!

Image Courtesy of Stephanie Weber

Pruning Roses

 Hybrid Teas, Floribundas, and

Grandifloras

• To encourage large blooms suitable for cutting, cut back all but 3 to 5 of the healthiest, most vigorous canes in early spring just as buds begin to swell

• Prune these 3-5 canes to 15-18” from the ground

• Prune away weak, small, or short stems (anything thinner than a pencil should be cut)

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Pruning Roses

 Climbing roses, Old-fashioned rambling roses

• These bloom on last year’s growth, so do not prune

until after flowering

• Remove oldest stems, leaving 5 – 7 strong canes

untouched. Remember, the stems you leave will bear next year’s flowers.

 Old Garden Roses

• Hard pruning can ruin their graceful shape

• Remove no more than 1/3 of each bush

• Generally remove old stems that are no longer

productive

Pruning Evergreens

 Most evergreens seldom require pruning

 Prune a little each year so that severe pruning is not needed

• It’s better to buy a dwarf plant than do a lot of pruning on many evergreens

 When pruning narrow leaved evergreens, never cut into

the bare wood beyond the foliage

• Many evergreens do not have buds on older twigs, and the shrub may never recover

 Only cut the central trunk if you are trying to eliminate a multiple leader (such as when the tree is young)

Pruning Evergreens

 Spruces, Firs, and Douglas Firs

• Have lateral buds that will grow if the terminal bud is removed

 Pines

• Removing terminal buds will take away growing points for that branch, leading to dead stubs

• To promote more dense growth you may remove up to 2/3 of the new growth

• Do NOT prune past current year’s growth!

 Arborvitae, Junipers, Yews, and Hemlocks

• Tolerate heavy shearing

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Activity

What to Cut

This Young Tree Needs Some Help

Image adapted from University of Minnesota Cooperative Extension

 There are six cuts that need to be made on this tree.

 Determine which

branches should be cut, and why!

This Young Tree Needs Some Help

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When to Prune

Yes, It Matters!!

When to Prune – Rules of Thumb

 Pruning at the wrong time of the year usually doesn’t kill your plant, but can damage it

 Continually pruning your plant at the wrong time CAN

cause permanent damage and/or death to the plant

 In general, the best time to prune is in late winter to early spring, before the season’s growth begins

• Generally, the worst time to prune is immediately after new growth begins in the spring

• The second worst time to prune is in late summer

 Dead branches can be pruned at any time

General Guidelines for Timing

 Prune before breakfast, not before bed

• Generally prune in the spring, not fall  Hair cuts after the prom, not before

• Prune spring plants right after bloom, not before  Diet before Vacation, not after

• Prune summer plants before they bloom, not after

 When you move, it is a good time to clear out the junk

• Root prune and top prune plants if they need it when you transplant them

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Spring Flowering Shrubs

Image courtesy of Stephanie Weber

Spring Flowering Shrubs

 Bloom in the spring on previous season’s growth

 Examples include lilac, forsythia, and rhododendron

 Pruning time will vary based on condition of the plant

 Shrubs only requiring light pruning

• Prune immediately after bloom

 Old, neglected, severely overgrown shrubs

• May require extensive pruning

• Rejuvenate by pruning in late winter or early spring (March to early April)

• This will reduce or eliminate this and possibly next year’s flower display, but greatly increase the long-term health of the shrub

Summer Flowering Shrubs

 Bloom in the summer on current year’s growth

 Examples include potentilla, Rose of Sharon, hydrangea, and spirea

 Prune in late winter or early spring

• This will allow for bloom in the coming summer

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Other Deciduous Shrubs

 Many deciduous shrubs don’t produce showy flowers, but may have striking bark, fruit, or fall leaf color

 Prune these in late winter or early spring before growth begins

 Do NOT prune these in late summer or early fall (any time after mid-July)

Roses

 Repeat blooming roses (floribunda, hybrid teas)

• Prune heavily in the spring, just as the buds begin to break dormancy (begin to swell)

 Roses that bloom once a

year (old-fashioned roses and climbers)

• Prune immediately after flowering

• Do NOT prune heavily in early spring, since they bloom on wood from the previous year’s growth

Evergreen Shrubs

 Examples of evergreen shrubs include juniper, yew, and arborvitae

 Prune in late March to mid-April before new growth begins

 Some light pruning may be done in late June or early July

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Deciduous Trees

 Examples of deciduous trees include oak, maple, and birch

 Deciduous trees may be pruned anytime during the year

 The BEST time to prune is late winter to early spring, before the leaves are out on the trees

• Some trees with high sap pressure (such as maple) will “bleed” heavily when pruned at this time, but this is not harmful to the tree

Image courtesy of Joseph O'Brien, USDA Forest Service, Bugwood.org

Deciduous Trees

 Avoid pruning oaks from

April 15 to July 1 because of the risk of oak wilt fungus.

 Oaks can be safely pruned

in February and March.

Image courtesy of Chris Evans, River to River CWMA, Bugwood.org

Fruit Trees

 Prune from late February to early April

 Spring and summer pruning

increases infection and the spread of fireblight • Plants susceptible to fireblight,

such as apple and pear, should ONLY be pruned during the dormant season

Image courtesy of Joseph LaForest, University of Georgia, Bugwood.org

 Fruit trees pruned in the fall may be more prone to winter injury

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Grape Vines and Raspberries

 Prune grape vines in March or early April

• A hard frost in late winter can damage the canes and buds if vines are pruned too early

• Vines will bleed heavily when pruned at this time, but the bleeding will not harm the vine

 Prune raspberries in March or early April

• Summer bearing raspberries should also be pruned in

the summer. Remove old fruiting canes after the crop has been harvested.

Annual Pruning At a Glance

 Late winter (before the leaves are out) • Deciduous trees (never prune oaks April 1 – July 1)

• Fruit trees (late Feb to early April)

 Late winter/early Spring (March to early April) • Summer-flowering shrubs

• Hard pruning of severely overgrown spring-flowering shrubs

• Other deciduous (non-blooming) shrubs

• Grape vines and raspberries

• Evergreen shrubs

 Late spring (May and June)

• Spring-flowering shrubs (when they’re done with their bloom)

Exceptions to the Rules

 Prune at any time to correct damage to limbs, vandalism, or hazards created by weather or other causes

 Formal hedges and specialty pruning like espalier and bonsai require more frequent maintenance than informal hedges, or plants maintained in their natural form

 Exact timing of pruning will vary across climate zones. Follow cues from the plant to determine ideal time of pruning.

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Love Hurts

What NOT To Do

Topping and Tipping

 Topping is the pruning of large upright branches between

nodes, sometimes done to reduce the height of the tree

 Tipping is cutting lateral branches between nodes to reduce crown width

 Consequences:

• Death of the cut branch back to the next lateral branch below

• Epicormic sprouts, which are only weakly attached to the steam and eventually will be supported only by a decaying branch.

Images from USDA Forest Service

Topping, AKA Tree Abuse

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Improper Cuts

 Improper pruning cuts cause unnecessary injury and bark

ripping (AKA, the Nearly Headless Nick cut)

 Flush cuts injure stem tissues and can result in decay

 Stub cuts delay wound closure and can allow pathogens

to enter the plant

Images from USDA Forest Service

How to Tell

 The quality of a cut is evident after one growing season

 A concentric ring of wound wood will form around a proper pruning cut

 Flush cuts (cutting too close) will show excess wound wood on the sides with very little on the top or bottom

 Stub cuts (cutting too far) result in dead branch tissue. Wound wood forms from stem/trunk tissue, so wound closing is delayed.

Bark Ripping

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Flush Cutting

Images courtesy of Joseph O'Brien, USDA Forest Service, Bugwood.org

Stubs

 The longer the stub, the more food you’ve set out for wood-decaying fungi

 If you can hang your hat on it, it’s too long!

Joseph LaForest, University of Georgia, Bugwood.org Joseph O'Brien, USDA Forest Service, Bugwood.org

Pruning Safety: Use Common Sense!

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Pruning Safety: Use Common Sense!

Images courtesy of Purdue Cooperative Extension, http://www.ces.purdue.edu/ces/vanderburgh/horticulture/weird/pruning.htm

Activity

Proper Pruning or Hack Job?

 Break up into groups and look at your handouts showing pictures of various pruning cuts.

• Was the tree in your picture properly pruned or not?

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Proper Pruning or Hack Job?

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Image courtesy of Fred Baker, Utah State University, Bugwood.org

Proper Pruning or Hack Job?

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Proper Pruning or Hack Job?

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Image courtesy of A. Steven Munson, USDA Forest Service, Bugwood.org

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Proper Pruning or Hack Job?

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Image courtesy of USDA Forest Service - Northeastern Area Archive, USDA Forest Service, Bugwood.org

Pruning

Resources

Resources – The Internet

 You can find a wealth of information by searching Google.com

 Only trust reputable sites

• Universities and Cooperative Extension offices are best

• USDA and other government sites

 Take what you read on store and company websites with a grain of salt

• Remember, just because they’re selling something

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Some Useful Web Pages

 Colorado State University Extension – “Pruning Flowering Shrubs”

• http://cmg.colostate.edu/gardennotes/619.pdf

 North Carolina State University Extension – “Pruning Shrubs” • http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/shrubs/text/pruning.html

 Pennsylvania State University – “Pruning Ornamental Plants”

• http://pubs.cas.psu.edu/FreePubs/pdfs/AGRS95.pdf

 Texas A&M Extension – “Follow Proper Pruning Techniques”

• http://aggie-horticulture.tamu.edu/extension/pruning/pruning.html

 University of Minnesota Extension – “Pruning Trees and Shrubs”

• http://www.extension.umn.edu/distribution/horticulture/DG0628.html

 USDA Forestry Service – “How to Prune Trees”

• http://www.na.fs.fed.us/spfo/pubs/howtos/ht_prune/prun001.htm

 Virginia Cooperative Extension – “A Guide to Successful Pruning: Pruning Basics and Tools”

• http://www.ext.vt.edu/pubs/nursery/430-455/430-455.html

 There are others!!!

Other Resources

 Extension Agents, Professors, Other Specialists

 Libraries and Bookstores