Tree and Shrub Pruning

Toso Bozic

Bioenergy/Agroforestry Specialist

Alberta Agriculture and Forestry

OUR Goal for Pruning????

Trees “pruned or not” around my house block

“Lion Tailing” pruning

Topping trees

Not healthy pruning

Photos: Heather Dickau

Chocking tree

Why prune trees ?

• to remove diseased or storm-

damaged branches

• to thin the crown to permit new growth and better air circulation

• to reduce the height of a tree to remove obstructing lower branches

• to shape a tree for design purposes

• To reduce potential for fire

• To encourage flowering, to promote fruit production

Myths about pruning

• Pruning is difficult

• Plants will die if they are pruned wrong time of year

• All pruning must be done during the winter

• Removing and Pruning trees is crime against nature

• Most trees need pruning

• Hedge shears is the all you need to do with shrubs

• Anybody with pick up truck , chainsaw, and pruners are expert

• All cuts must be treated with paint

Basic Principles of pruning

• Visualize the shape plant at maturity – how tree will look like after pruning

• Remove dead, damaged and diseases wood

• Select the main scaffold branches or main stems that you wan to keep

• Remove weak crotches, crossed branches, suckers and watersprouts

• Thin crown that will promote healthier plants by getting more air and sunlight at center of crown

• Cut back to branch collar as to leave the smallest wound possible

• Remember that too much of anything is not always best – you can always prune next year

Importance of early correct pruning

Branch Angles

Pruning techniques

• Cleaning is the removal of dead, dying, diseased, crowded, weakly attached, and low-vigor branches from the crown of a tree.

• Crown Thinning is the selective removal of branches to increase light penetration and air movement through the crown. Thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree’s natural shape.

• Raising removes the lower branches from a tree in order to provide clearance for buildings, vehicles, pedestrians, and vistas.

• Reduction reduces the size of a tree, often for clearance for utility lines.

Crown Thinning

• Thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree’s natural shape

• Branches with strong U-shaped angles of attachment should be retained

Crown Rising

Pruning cuts

How to Prune?

Proper pruning

Proper 3 cut pruning

Proper cuts

Correct position of pruning tools

Improper pruning

Stubs

Hedge Trimming

Shearing

When to prune?

• Coniferous can be pruned any time of year

• Hardwood trees and shrubs without showy flowers:

– prune in the dormant season to easily visualize the structure of the tree,

– to maximize wound closure in the growing season after pruning,

– to reduce the chance of transmitting disease, and

– to discourage excessive sap flow from wounds

• For majority of tree the best is time from March to mid-April or during the winter

• Birch and Maple – prune ONLY during growing season – June and July – leaves must be fully developed

• Elm tree – DO NOT prune from April 1 till October 1

How much to prune?

• Every time when you prune it is stress for tree and increase vulnerability

• It open opportunity for insect and diseases to invade trees

• Generally speaking no more 25 % of alive branches

• The amount of live tissue that should be removed depends on the tree size, species, and age, as well as the pruning objectives.

Pruning trees 0 to 20 years of age

• Train the leader

• Build a strong structure

• Balance branches

• Reduce co-dominant branching

• Reduction pruning on lower branches

• Slowly remove lower branches

Pruning tree after 20 years of age

• Growth is slowing down at this stage

• Balance as needed

• Remove poor crotches

• Reduction pruning on co-dominant leaders

• Repair storm damage, wind, ice and flooding

• Prune to reduce fire hazards –eg remove dead branches

Pruning Evergreen trees-spruce, fir, pine, cedar and juniper

• Requires very little or no pruning

• Keep in mind that only 1/3 of the new growth should be removed at one time.

• Never make pruning cuts behind the green foliage on a branch. Bare wood will seldom form new buds and the stubs will die without producing new foliage

• Pine – mid June

• Spruce and Fir – Mid may till mid June

• Cedar and Juniper – more clipping then pruning –early spring till mid June

• Damaged top leader needs to be removed and one side branch need to re-established as leader

Evergreen pruning

Coniferous pruning – white spruce

• Lower branches are dead and can be removed

• It reduce potential for fire

• Provide more sunlight for understory vegetation

• Relatively easy to prune and quick recovery

Poplar and Willow pruning

Prunus and Malus species- mayday, Shubert chockecherry, pincherry, crabapple etc

• They are in same Rose family of species as apple, howthorns, roses and others.

• Prunus species have single seeds, hard central “stone”

• Many species are cyanogenic (toxic) –seeds and leaves or after they have been decomposed or crushed

• Crabapple and Shubert’s are grafted onto suckering rootstock so you need to remove suckers annually

• Blacknott is huge problem in Prunus genus and early pruning is the only way to reduce potential of spreading disease

Species affected by Black Knot

Pruning apple trees

• Before you do pruning please visualize how tree will look like – walk around

• Train as much and remove as little possible

• Remove any branches that are growing inside – leave center of tree open

• Remove any 3D (Dead, diseased, and damage) branches

• Remove all suckers and branches that are downward branch

• Rubbing and crisscrossing branches remove

• Competing leaders

• Narrow crotches

Before and after pruning of apple

Pruning Shrubs

• Shrubs bloom before June 20 should be pruned immediately after bloom period

• Shrubs bloom after June 20 should be pruned in dormant season or just before growth in spring

• Not all shrubs needs to be pruned, not every year and not hard

• Many flowering trees/shrubs (eg crabapple, hawthorn, pin cherry, chokecherry, etc) are susceptible to Fire blight and Black knot diseases and pruning can spread these terrible diseases

Shrub pruning prior June 20

• Aim is to promote more flower buds for next year

• Prune weak stems and heading back selected stems to promote strong lateral shoot

• Examples are: Dogwood, Lilacs, Spirea varieties and Mock orange (philadlphus) flowering plums, hawthorn, forsythia, crabapple, Viburnum, mountain ash etc

• Prune immediately after bloom has finished

• Unpruned shrubs of this type become twiggy

Late flowering shrubs – bloom after June 20

• You want create a large number of strong, current year twigs and thereby large number of flower buds

• Potentila retain their shape naturally and little pruning is required

• Spireas requires severe cutting back of all stems

• Potentials requires very minimal pruning

• Lilacs and Honeysuckles requires regular pruning

• Rejuvenating lilac you can cut up to 2 feet from ground

• Evergreens shrubs most of times requires NO pruning

Lilac pruning

Pruning Roses

• In wild roses produce strong new shoots from near the base of plant each season

• Prune during the winter – march/april just before season starts

• Deadheading during summer – prune to above 2 to five leaflets buds

• Cut back into healthy wood –

• Cut outward pointing bud to encourage an open center

• Cut any diseased or damaged branch

• Remove all thin, weak canes that are smaller than a pencil in diameter

Pruning cuts –roses

Root Flare

Circling roots

Root pruning preparation

Shelterbelt fire hazard pruning

• Reduce potential for fire

• Reduce potential for various human or livestock injuries

• More pleasant for many people

• Most of internal branches are dead and can be removed

• Increase the value of the logs

• Produce better lumber – knots free

Shelterbelt fire hazard pruning

Photos – Heather Dickau

Tools

Pruning tools

• Clean and Sanitized (mostly by diluted bleach)

• Must be Sharp

• you get what you pay for, so cheaper tools....usually are !!!!

• Buy only tools that you really need

• Clean up and sharpen tools after you finish work

Summary

• Ask yourself why do you need to prune any trees or shrubs – is it MUST or just aesthetic?

• Do proper pruning

• Use sharp and clean tools

• If trees are infested remove these branches and burn them –don’t spread diseases

• Always ask expert on this matter

• Use books

• Have fun

“We must understand that our natural resources(water, forest, agriculture, energy is not only an economic value, but also social, religious, spiritual, cultural and environmental value as well and that world of future will demand all above” – Toso Bozic

Thank you !!

For more information

• Toso Bozic

Phone: (780)- 415-2681

Cell: 780-940-6107

E-mail: toso.bozic@gov.ab.ca