How to Prune an Olive Tree: Cut for Light, Air and Next Year's Fruit

Fruit comes on last year's wood

This is the rule that governs every cut you make. Flowers, and therefore fruit, are borne on shoots that grew the previous season. Shear the whole outside of the tree into a neat ball each spring and you remove exactly the wood that was going to fruit, which is why so many tidily clipped olives never crop.

It also means old, bare interior branches carry nothing. The productive part of the tree is a shell of one-year-old shoots, and your aim in pruning is to keep light and air reaching enough of the interior that new shoots keep forming there rather than only at the very tips.

When to cut

Prune in late winter or early spring, once the worst of the cold has passed but before growth restarts. Cutting in autumn leaves fresh wounds through the wet season and stimulates soft growth that frost then kills.

A light tidy is possible after flowering if the tree is badly out of shape, but avoid heavy summer cutting on a tree carrying fruit. Olives commonly take a year off after being pruned hard, so if you have to reduce a tree substantially, expect to sacrifice the next crop and do it in one go rather than dragging it out over three seasons.

The order of cuts

Work through the tree in a fixed sequence rather than wandering around it. By the time you have done the first three steps below, most trees need very little else, and stopping there is usually the right decision.

1. Take out dead, damaged and crossing wood Cut back to clean wood where the scratch test shows green. Branches that rub each other create wounds that let disease in, so remove the weaker of any crossing pair.
2. Remove suckers from the base Olives throw vigorous shoots from the base of the trunk and from below any graft. Tear or cut them off flush as low as you can reach. Left alone they take a large share of the tree's energy.
3. Open the center Take out branches growing straight into the middle of the canopy, and thin the interior until you can see daylight through the tree. Traditional practice is to open the crown enough that a bird could fly through it.
4. Shorten only what is out of proportion Cut long, whippy shoots back to a side branch pointing outwards rather than snipping the tips. Never leave a stub; cut just beyond the junction.
5. Stop at a quarter of the canopy Removing more than about a quarter of the leafy growth in one year pushes the tree into producing water shoots and costs you the following season's crop.

Sterilize the blade between trees, and between cuts if you are removing diseased wood. A wipe with alcohol is enough and takes seconds.

Keeping a container olive to size

A potted olive can be held at four to six feet (1.2 to 1.8 m) for many years, but only if you prune to a framework rather than clipping the outside. Choose three to five main branches, keep the center open, and each spring shorten the previous year's growth by about a third on some shoots while leaving others full length.

Leaving a proportion of last year's shoots untouched is what keeps a pot-grown tree fruiting. If you clip every shoot every year the tree stays neat, stays green, and never flowers. Alternating which shoots you cut, so that roughly half the canopy is untouched one-year-old wood, gives you shape and a crop at the same time.

Renovating a neglected tree

An old olive that has become a dense thicket can be brought back, but over three years rather than one. In the first spring take out the dead wood and the worst crossing branches only. In the second, remove one or two of the largest congested limbs. In the third, shorten what remains and settle on the framework you want.

Olives regenerate from old wood readily, so even a severely cut tree will shoot. What it will not do is fruit while it is rebuilding, and it will throw a mass of vertical water shoots that need thinning out each summer. Record the date and the extent of each stage of the renovation, because the whole point of spreading the work is losing only one crop rather than several.