The Good Life

How to prune & more importantly, how NOT to prune

Trees don't care how they look. People struggle and stress over pruning choices but understanding the why and what makes it simpler. You can't really stuff it up and kill the tree, although you might miss a harvest.

Why prune?

You don't prune for the benefit of the tree.

Humans believe that we must prune fruit trees. But trees are quite happy if no-one comes along and amputates their branches every year. They survived for millions of years without the need for chainsaws or secateurs.

Pruning is a relatively new practice developed in the last 100 years, mainly to make harvesting more cost-effective.

The main reason you'll prune a home orchard is for convenience, so you can: get the mower past;

reach the fruit; fit more trees into a smaller space;

remove diseased/damaged branches. Bad pruning can be disadvantageous for the tree; some judicious snips can be beneficial.

Pruning at planting

It's beneficial for bare-rooted trees to receive a ‘hard prune' at planting (see the pruning guide at the bottom of page 44). Potted trees also benefit to a lesser extent.

The branches and leaves of a tree are proportional to the roots. Whenever you prune it, you're reducing its ability to feed its root mass, which then restricts itself accordingly. When you transplant a tree, its roots are being disturbed, and it's best to reduce the leaf area correspondingly to keep it in balance.

If you don't, when leaves start to grow in spring, there aren't enough roots to sustain them. This drains the tree of energy, inhibits new growth, and weakens it, making it more susceptible to pests and disease. It will take time to rebalance itself and catch up.

It's estimated you reduce a bare-rooted tree's roots by about a third at planting time and a potted tree's roots by approximately 10%, so that's how much you should prune from its canopy.

Pruning basics

Any pruning other than the 3Ds (see page 45) is for your convenience. You can prune 'up' from the base so you can walk under trees, or prune 'down' from the top to reach the fruit. It's very difficult to have a tree that can fulfil both requirements.

You can also prune into topiary, shapes that grow along fences, or ones that go over arches.

There's no right or wrong method, but pruning always has consequences:

it reduces the leaf area (and therefore the root area the tree can support), and its ability to harvest sunlight (and uptake nutrients); it reduces the tree's fruiting capacity. A tree will direct a lot of its energy into replacing anything you remove, energy it could direct into fruit production or disease and pest immunity.

If you prune, help the tree by mulching it heavily with organic matter, so it gets extra nutrients to help it recover.

Timing

This is important to prevent unwanted regrowth and diseases.

Always prune on a fine, dry day

Bacteria and fungi thrive in warm, moist conditions, floating around in the air looking for an open cut to infect.

Don’t prune in spring and autumn

A tree's heaviest sap flows occur during the high growth periods of spring and autumn. Pruning causes the wounds to stay open longer, extending the time the tree is vulnerable to airborne disease.

If you do have to prune during these times, I'd recommend painting a sealant over the wound immediately (see page 47 for why this is an exception to my 'no sealant' policy).

Sheryn's rule: pick, then prune

This means summer fruit – peaches, nectarines, plums, apricots, etc – are pruned in mid-late summer. Autumn fruiting trees – apples, pears, quinces, feijoas, persimmons etc – are pruned in winter when the growth phase has passed.

If pruned in winter, summer fruit often sends up tall skinny regrowth called watershoots the following spring. This is because the tree has gone to sleep over autumn and winter, thinking it has big branches, pathways that it will direct a lot of energy into in spring. Remove the branch or branches, and there's nowhere for that energy to go, so the tree redirects it into new, long, green watershoots that need removing. Prune in summer and you save yourself (and the tree) the trouble.

The exception to the rule

In New Zealand, the exception is citrus.

This beetle can apparently smell a fresh prune from 2km away. It burrows into open wounds and infects the tree.

It only flies in warm weather. In Northland, this can be all year round; in more temperate climates, it's September to March.

If you must prune during the borer beetle danger season, use a sealant or pruning paste.

In colder climates, regrowth after pruning will be fresh and susceptible to frost.

In my South Waikato orchard, these limitations mean I can only prune citrus safely in winter when trees are laden with fruit. There is waste, but it means I do foil the borer beetle.

1 DISEASE

Judicious pruning can stop diseases from spreading. Simply cut off an infected branch or branches. Cutting tools must be sterilised, before, during, and after the operation, or you'll spread the disease with your blade to the next tree you prune. You can:

dip blades in a bucket of bleach solution;

wipe them with a rag soaked in methylated spirits;

spray them with a steriliser or sanitiser.

It's good to regularly sanitise equipment when pruning, but be especially pedantic if wood is diseased.

Prune back to clean, healthy wood. Remove and burn (or bag, seal and dispose of) all infected wood. 2 DAMAGED

Damaged bark is an entry portal for infection. Prune back to an easy-healing straight cut: •

where branches are rubbing on each other; • if the bark is open and split.

The exception is if a branch splits due to too much fruit. If it's still attached to the tree, I leave it to ripen the fruit, then prune it back after harvest. The risk of disease spreading is less in hot, dry, summer weather, and I've found the benefits usually outweigh the risks. 3 DEAD

Trim back to healthy wood that can heal over, otherwise the tree is continually expending energy to fight against dieback.

Fruit trees fruit on branches of different ages. In most cases, removing younger branches (1 & 2) will reduce fruit production.

Apples

Most apples, pears, and plums fruit on 'old' wood (2). Some apple varieties are tip bearing, or partial tip bearing, which means they fruit on the tips of branches (1) instead of spurs on old growth. These include: Monty's Surprise;

Granny Smith;

Peasgood Nonsuch;

Bramleys;

Gala.

Other fruit

Peaches, feijoas, figs, and the bulk of apricots fruit on wood that is two years old – that is, last year's new growth (the fruit bud takes two years to develop).

Only figs (which also fruit on 'old' wood), persimmons, and tip-bearing apples fruit on new growth.

A nectarine in a vase or V-shaped form.

In a case like this, let the fruit ripen before you prune the damaged branch.

1. 'Young' wood (under 1 year old) is smooth and supple, and has small leaf buds. Some trees only bear fruit on this wood so you don't want to prune it off. 2. The thicker, harder, rougher look of 'old' (2 years+) wood, with fat, feathery fruit buds. Most trees bear fruit on this type of wood.