pruning

Pruning Cuts

Growth definition pruning:
Establishes good structure in young trees. Done in the first years after planting.
Maintenance pruning:
Maintains the shape and size of the tree, makes for fuller foliage, lets sunlight reach the plant interior, improves flowering and is done to remove excess, dead, weak or gangly branches. Done annually.
Rejuvenation pruning:
Drastic cutting right back of branches to stimulate the growth of new shoots. Is done over more than one season and only as needed.
Lopping:
Cutting off of larger branches and is done as needed.
Fruit-tree pruning:
Encourages the production of fruit on fruit trees and shrubs. Is done every year.

How to Prune

Here are a few simple rules of thumb for pruning:

Cutting angle:
Cut little branches diagonally at a 30º angle about 0.5 cm above a bud and run your cut in the same direction as the bud.

Cutting back a long branch:
Using pruning shears or a saw, cut the branch at the branch crotch, where a secondary branch leads out in the same direction as the branch you are cutting and heads preferably horizontally or along the underside of the branch you are cutting.

Reshaping the leader shoot:
The leader shoot is the prolongation of the trunk at the summit of a tree. If the leader has been broken or if there is more than one leader, choose the strongest and the most vertical and cut diagonally just above it. If necessary stake the leader to keep it straight so that it remains the leader.

Removing a branch at the trunk:
Don't cut a branch flush with the trunk. Cut it just above the branch collar. This collar is, in fact, scar growth that will quickly close the cut.

Removing thicker branches (3 cm in diameter or more).

A large branch may tear bark from the trunk as it falls, so here's a solution. Make a cut on the under side of the branch you are removing, about 30 or 40 cm from the trunk.

Then saw off the branch just above the branch collar. Remove the remaining stub by cutting right along the branch collar.

Protective tree paint:
It is not recommended to apply tree paint to a fresh cut. Leave it and it will dry faster and heal itself naturally. It produces its own enzymes against rot and disease.

Pruning Trees

Lopping and rejuvenating pruning is usually done in March or April before the buds come out. Birch and Maple, however should be pruned in the fall after their leaves have fallen. If you prune them in the spring they will lose too much precious sap, causing the branch that is left to dry out and die. Never cut more than one third of the crown. Some trees, such as the apple and the linden, produce suckers at their base. They should be removed as soon as they appear.

Pruning Shrubs

Maintenance pruning is done on shrubs to lighten up branching that has become too dense or to shape the plant or limit its growth.

Don't do any drastic shearing; go at it one branch at a time. Start by removing any old, dead or weak branches and branches that are too long. Always cut just above a bud or a secondary branch.

The time for pruning will depend on when the shrub normally comes into flower:

Shrubs with decorative foliage (dogwood, ninebark) and those that flower on this year's new wood (spike-flower hydrangea, potentilla, elder) should be pruned in the spring in April or early May. These are generally shrubs that flower in Mid-summer or in the fall.

Shrubs that flower on last year's wood (lilacs, weigela, Van Houtte spirea) should be pruned only after they have finished flowering. These shrubs flower in the spring and early summer.

Rejuvenating

Rejuvenating involves pruning neglected shrubs or shrubs that have pretty well stopped flowering or that have become too big for your garden.

This type of pruning can be done over 2 or 3 years. It involves progressively removing old dead wood and trimming back branches, leaving only a few young and vigorous branches. Progressive rejuvenation is effective on broadleaf evergreens such as rhododendrons and shrubs that are fragile or slow-growing such as the Japanese maple and the ornamental cherries.

Rejuvenating a shrub can also mean cutting the whole shrub right back to 15-20 cm from the ground. This heavy pruning is suitable for fast-growing shrubs such as ninebark, honeysuckle, dogwood, spirea and rugosa roses. These plants are able to produce lots of new shoots quickly and will grow back nicely all in one season.

Pruning Conifers

Some conifers bounce back better than others after a pruning. For small gardens opt for dwarf species or slow-growing species.

Large branches of tall conifers should be removed in the fall, in October or November, so that the tree doesn't lose too much sap.

Young shoots on conifers are generally pruned around mid-July, after their first growth spurt. Avoid cutting branches that are over 2 years old because they are often too old to produce new needle or foliage growth. (Ex. cedar, yew). Fir, spruce and pine are generally pruned in early summer, in June. Cut back new shoots by 1/3 while the needles are still furled. To avoid having the needles go brown on their tips, pinch off the new shoots with your fingers.

Prune the branches of juniper and false cypress at the branch crotch of a new branch.