The way to manage the shape and size of an established citrus tree is to prune annually. The best window is in late winter to early spring, when flowers are starting to form for the next season’s crop (hold off until late sping in frosty areas). But do not go for the all-over haircut! Here’s how to prune without stressing the tree and robbing yourself of a crop.
- Prune selectively Don’t give the canopy an all-over haircut, as it removes all of the fruiting sites so you’ll get little or no fruit next season. Instead, focus on cutting back a selection of the longest and most offending branches. These include tall upright branches and side shoots that grow beyond the desired size and shape of the canopy.
- Cut with care Prune to about 30cm inside the line of the canopy you want to maintain. These cuts will shoot, then start flowering and fruiting again in the following season. Aim to cut out about 20 per cent of the canopy each year using this approach. After five years or so, you will have potentially given the entire canopy a chop, without denying yourself a crop or stressing the tree.
- Tidy inner branches Prune out any dead, damaged and diseased wood along with any branches that are crossing and rubbing. The bark at rubbing points eventually wears and exposes the inner wood to infection.
- Trim lower canopy Prune any branches that are touching or nearly touching the soil, lifting the lower canopy to about 1m above the ground. This helps to maintain airflow through the canopy and reduces the potential for fungal diseases.
- Check for pests Look over the outer foliage of the canopy for unusual swellings in the stems caused by citrus gall wasp. This is a wasp that lays its eggs in the soft young stems, causing them to swell. Severe infections can weaken the tree, so prune them off and burn them, or seal in a plastic bag and put them in the bin before they emerge and reinfect your tree. Tiny pinholes on the galls indicates that the baby wasps have already emerged, so there’s no need to remove these.
You’ll find lots more information to help you care for your citrus trees, including expert advice on planting, training, watering, feeding and dealing with pests, in the August 2021 issue of ABC Gardening Australia magazine, out now.