Gardening: Trim trees make the cut

Pruning trees is easy - make a shallow undercut; cut the heavy weight off the branch; and cut the remaining branch stub from just outside the branch base or 'collar'. Photo / Meg Liptrot

Winter is the ideal time to haul out your secateurs, suggests Meg Liptrot.

A fine winter's day is a good time to get some formative pruning done. As the "bones" or structure of the garden are revealed, hedges can be clipped, and the pruning and opening up of trees can happen from late autumn, after deciduous plants are left to drop their leaves first. Pruning is best on a dry, sunny day, as fungal spores are less likely to infect fresh cuts on a tree and cause disease.

Gardening in winter has additional benefits - you're not likely to get sunburnt, and you'll feel virtuous emerging from winter hibernation for a couple of hours. A little judicious pruning may also let some winter sunlight into your home.

Another excellent reason to prune now is to remove dead branches and twigs which are host to pest insects and their eggs over winter. Prevention is better than cure.
Passionvine hoppers are a case in point. Their egg deposits look like long rows of little brown dots, each smaller than a pinhead, and are usually found on dry twiggy material. This material can be chopped up and added to a hot compost. Leave them to hatch and you are likely to have a bug invasion in summertime.

The golden rule is to prune only when the plant isn't stressed doing something else - such as dropping leaves or producing new leaves and blossoms. You can also prune in summer to remove excess growth and to allow air circulation for the tree.

There are a few tips when pruning. The most important is to stand back and assess the shape of the tree, then make your cut. Do this often to avoid creating an unbalanced tree. It's better to look twice, and cut once. Look for overcrowded and crossing branches, particularly with fruit trees. A good rule is to cut no more than 25 per cent of foliage from a tree each year.

Step 1

Make an undercut so that bark is not stripped off the tree when the heavy foliage comes down.

Step 2

Cut the heavy weight off the branch just above the undercut.

Step 3

Finally, cut off the branch from just outside the swollen branch base or branch collar (usually a few centimetres out from where it's attached to another branch, or the trunk).

If you cut too close to the attachment point and make a flush cut, you remove a special layer of growth cells, and the tree can't cover the damage with new material. What you want to see in a year or so is a doughnut-shaped formation called a "callus" grown over the cut from the branch collar.

Remove diseased wood from your property, but hire a chipper and make mulch from healthy offcuts. Cut up larger material for next year's firewood.

Pruning tips

Deciduous fruit trees:

* To encourage fruit, prune branches to be horizontal rather than vertical.

* Always prune to an outward facing bud or branch.

* Find out what fruiting buds and spurs look like, and where the fruit is likely to form on your type of fruit tree.

* Apple and pear trees produce fruiting buds which can turn into spars on second year wood, they can be kept indefinitely, but old spurs should be thinned.

* Fruit trees can be tip bearing such as fig and some apple and pear varieties.

* Peaches produce fruit on last season's new growth. Prune old growth to encourage this.

* Stone fruit are best pruned in summer to prevent fungal diseases.

* Keep your tools sharp, and clean your equipment with meths between trees.