Without pruning or training, citrus trees grow naturally into bushy trees and will initially crop well. However, trees will eventually become overgrown with high proportion of dense, unproductive and spent wood. If trained, shaped and pruned in a specific way, trees will be healthier, easier to manage and will crop more reliably.
The most productive growth and fruiting occurs, in the outer 90cm of the tree canopy. So the optimum tree canopy size is no more than 2 to 3 metres. A large sprawling canopy takes up a lot of space and produces no more fruit than a compact well-managed one.
The number of terminal (tip end) shoots, determine fruit quantity. More shoot tips results in more fruit. Regulating the number of shoot terminals is the best way to achieve a balance between foliar growth and fruit numbers.
Young Trees and shaping
Retain three to four main branches 50 to 70 cm above ground level. As the young tree grows, tip prune young shoots to keep the tree compact. The ideal shape is an upright tapering cone. Maintain this shape by tipping shoots and cutting back over vigorous water shoots in late winter. Early and continuous shaping minimises heavy cutting later on.
Maintaining the shape
Citrus trees respond well to shaping. You can even prune them with hedge clippers. Trim any untidy growth to maintain the desired shape. The best time is after harvest in spring. Early pruning promotes early summer growth, that will mature before the summer heat and the arrival of pests such as leaf miner.
Overgrown citrus trees
Older, overgrown citrus trees can be reworked to the desired shape using secateurs, hedge clippers or a chainsaw.
Very old (over 25 to 30 years), weak or disease affected trees may be cut back to induce further fruiting. However, old trees like this are at the end of their productive life and are often better off removed or replaced.
Want to know more about Growing Citrus in Melbourne?
This is Part 4 of a 5 part guide to growing citrus in Melbourne. The links below will take you to the other four parts of our Melbourne citrus growing guide.
Our citrus growing guides are based on my own experience, as well as the following two books. They are both invaluable resources for the home gardener based in Melbourne. I strongly recommend you have a read of both if you want to know more about growing citrus in Melbourne:
Bruce Mophett & Ian Tolley: Citrus, A Gardener’s Guide, 2009.
Louis Glowinski: The Complete Book of Fruit Growing in Australia, 1997.