Pruning and care of fruit trees
Pruning and care of fruit trees
First published in July 2022
Top tips
- follow the timetable below for individual fruit trees
- prune on a warm, dry day, especially for apricots and cherries
- avoid using wound healing sprays
- remove suckers
- avoid Bordeaux mix and use lime sulphur instead
Over the years advice on when to prune stone fruits has changed while advice on pome fruits – apples, pears and quinces – has remained the same. Here’s the current advice from Louis Glowinski, Australia’s foremost expert on all fruit trees, about when to prune stone fruit and pomes.
Prune at the following times:
- peaches and nectarines – new growth lightly in summer and complete the prune in autumn
- plums – after harvest in late summer or autumn
- cherries – after harvest in late summer
- apricots – after harvest in late summer
- apples, pears and quince – in winter when leafless
If you need to prune plums, nectarines and peaches early-mid winter, this is ok but make sure the weather is dry. Cherries and apricots however should be pruned late summer or not at all.
Stone fruit
All stone fruit trees benefit enormously by being pruned on a warm, dry day preferably with a breeze as this allows the cuts to dry out quickly and prevents bacterial infection and canker. Spraying with lime sulphur protects trees from fungal diseases and pests. Spraying should occur when the tree is leafless but there is a difficulty this year (2022), with some trees maintaining some leaf cover while at the same time the buds are swelling. Ideally, there should be a decent gap between trees being bare and bud swell, but with the climate changing, that’s sometimes impossible to achieve. In this situation prune while the last leaves are on – don’t wait for bud swell. Once leaves are on the tree, it is too late to spray as both leaves and flowers will burn.
Pomes
This is the time – mid-winter – to prune apples, pears and quinces. Prune on a dry day.
Leaf curl on peaches and nectarines
Spraying to prevent leaf curl (Taphrina deformans) happens in winter. Spraying with lime sulphur won’t always prevent total infection as spores are carried by wind and rain and you may get a small outbreak in spring. While unsightly, leaf curl will not affect fruiting except in very young trees. If you are worried about it, pick off the affected leaves and bin them, making sure to remove any from the ground as these will reinfect the tree. In fact reinfection may have come from litter beneath the tree in the first place as Taphrina deformans survives over winter on tree limbs and fallen leaves. Wet weather during spring escalates the development of curly leaf especially if the rain is mild.
Wound spray
Avoid spraying with a wound heal product. This has been widely discouraged since the 1950s and does more harm than good. Trees need to form wood callouses on pruning wounds. Spraying or painting a wound prevents oxygen getting to it and results in poor callous development, which allows disease to enter the tree.
Suckers
Suckers grow out of the ground around the tree base or out from the lower trunk below the graft. There are 2 schools of thought on sucker removal. The first is to remove suckers when they appear (or anytime you notice them), as they weaken the tree and the second is to remove them in summer when the soil is dry, to prevent fungal infection taking hold on the pruning cuts. My preference is to remove them when I notice them.
Suckers can be caused by damage to the roots so prune off any damaged roots before planting. Be very careful weeding or cultivating around the base of the tree as you may inadvertently damage roots close to the surface. Cut suckers out with sharp secateurs at ground level or close to the trunk if coming from beneath the graft. It can be, and usually is, a recurring job!
Spray fruit trees when leafless with lime sulphur.
Lime sulphur is both an anti-fungal and a pesticide. It is effective on stone fruit and almonds for leaf curl, freckle, rust, shot hole, brown rot, bryobia mite and San Jose scale. Apply while trees are leafless prior to bud swell. Be sure to cover the tree 360 degrees around, making sure all limbs and crotches are wet as this is a contact spray. In fact, clean out any crotches of dead leaves and insects before spraying. (A crotch is the V shape where the trunk meets the branches, and a perfect place for litter to accumulate).
Lime sulphur protects pome fruit from black spot, several mites, San Jose scale and powdery mildew. Spray when the tree is leafless. It is not suitable for Delicious or Cox’s Orange Pippin apples.
The rate of application for both stone fruit and pomes is 50ml per litre of water. Keep swilling the spray container to keep it well mixed, and so it won’t clog the nozzle.
Avoid Bordeaux mix which is banned in the EU.
Bordeaux mix (copper sulphate) has been used since 1882. Invented in France and sprayed on grapes, it prevented fungal diseases in French vineyards and was a great boost to agriculture for over 100 years. However it is now banned in 17 EU countries and Great Britain because of its environmental impact. Bordeaux mix firstly contains a heavy metal – copper – and over time builds up in the soil as a heavy pollutant. Secondly, it is toxic to earthworms, fish if it enters waterways, beneficial insects including bees and ladybirds, and livestock. It also degrades fertility and soil microbiology. In Australia it can still be used as it is categorised as ‘organic’ but hopefully this will change. If you want to use the last of your Bordeaux then wear protective clothes, glasses and gloves as it is toxic to humans. Cover the soil beneath your trees with newspaper or cardboard to protect it from drips and bin the covering after spraying. Apply to bare limbs only. Bordeaux is an anti-fungal but not a pesticide which is another reason to spray with lime sulphur. (See below for a link to a more comprehensive article on Bordeaux).
References:
Glowinski, Louis. The Complete Book of Fruit Growing in Australia, Lothian, Reprint 2005
For reasons not to use tree wound sealant
For suckers, this is an excellent video
Written by Robin Gale-Baker
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