When to prune olive trees: the right calendar and the mistakes that cost you the harvest

The question comes every year, always at the same time: when should you prune an olive tree? The short answer is "you start in early December, as soon as the harvest is over". The useful answer is a bit longer, because the window stays open for months, because there's a good two months' difference between an olive grove in Salento and one on Lake Garda, and because the right month is no use if you then cut badly.

Below you'll find the real calendar, the logic behind the dates, and the six mistakes we hear about most often from people who call us after losing a season's crop.

The principle: prune when the tree is not working

The olive is an evergreen and never goes fully dormant like an apple tree, but in winter it slows down: that is the moment to step in. The window opens and closes on two facts:

• it opens when the harvest is over — by then the tree has given what it had, there are no olives to protect and the tools are still in the field;
• it closes when spring growth starts — cutting once budding is under way means throwing away energy the tree has already spent.

Between those two moments there are three or four months of work, not two weekends. The only limit to respect is cold: do not prune with a hard frost on the way, and never cut frozen wood. In the South or along the coast the window is very long; in the North or at altitude, watch the forecast and, if the winter is harsh, leave the work to the tail end of the window.

The calendar, region by region

South and islands (Puglia, Calabria, Sicily, Ionian Basilicata)

From early December to March. It's the longest window in Italy, and you start as soon as the harvest closes, with the nets still to fold away. Use it to spread the work out: on a mature grove, pruning done calmly in December is worth more than a rush in March.

Centre and Molise (Tuscany, Umbria, Marche, Lazio, hilly Abruzzo and Molise)

From December to March, watching the forecast. You start after the harvest and carry on all winter, skipping the weeks with hard frosts announced. In the colder inland areas it pays to leave the most exposed plots for last.

North and high-altitude areas

Here winter really bites: you work in the tail of the window, from late February to April, and at altitude even the first week of May. Better late than frozen.

The practical rule that works everywhere: start when the olives are at the mill, stop when the tree gets going again. Once the shoots begin to lengthen and the local almond trees have been in bloom for a while, the window is closing.

Why it pays to start right after the harvest

The temptation is to put it off to late winter, when the days get longer. In the field, though, the season is better organised the other way round, for three concrete reasons.

The tools are already out and the crew is there. If you finish harvesting in late November you still have nets, ladders and people in the field: carrying straight on costs far less than setting everything up again in March.

You can see the tree. Freshly stripped of its olives, the structure is readable: you can tell which branches have produced, which need renewing and where the canopy has closed up. In March, with the shoots coming out, the same reading is harder.

The work spreads out. Three months of window means pruning when the weather allows, not when the calendar squeezes you. Over a hundred trees, that's the difference between a job done and a job rushed.

There is only one limit to respect: frost. Don't prune with a hard frost forecast for the following days, and don't cut frozen wood at all. Where winters are harsh, leave the most exposed plots for last.

The period to really avoid is August: at that time the tree is differentiating next year's flower buds. Cutting then means deciding, without knowing it, to have fewer olives.

The only summer pruning that makes sense: green pruning

Between June and July you can intervene lightly, and it's worth doing. This isn't real pruning: you remove by hand or with light shears the water sprouts (the vertical shoots growing from the branches) and the suckers (those growing from the base).

These are branches that will never produce and meanwhile eat up sap and light. Removing them in June, while they're still soft, takes ten minutes per tree and greatly reduces the work of the following winter pruning. But be careful to leave a few on the branches as sap drawers: they keep circulation alive in the older parts.

Before cutting: where does this tree bear its olives?

This is the part that makes the difference between pruning and random thinning.

The olive bears fruit on the previous year's shoots. Not on old wood, not on the current year's growth. The branches that will carry olives are the thin, flexible ones, often pointing downwards or outwards, that grew last season.

Two practical consequences follow:

• the pruner's job is to renew, that is, remove wood that has already produced to make room for new shoots that will produce next year;
• hanging branches are not branches "to clean up": they are often the ones most loaded with flower buds. Removing them systematically to tidy up is one of the fastest ways to empty an olive grove.

The shape: polyconic vase, but without dogma

The most common training system in Italy is the polyconic vase: a low trunk, the main scaffold branches at about 0.8-1.2 metres from the ground, 3-4 branches opening outwards at around 45 degrees, and the centre of the canopy kept open.

It lets light and air into the tree: the olive produces where the sun reaches, and a closed canopy is also a damp canopy, and therefore more exposed to fungal diseases. The low trunk is for you, so you can work under the canopy without a ladder.

That said, not all cultivars have the same habit. A Leccino and a Frantoio don't behave like a Coratina or a Nocellara. Forcing the same geometry on every tree is a mistake: the shape must be adapted to the natural habit of the cultivar, not the other way round.

The well-made cut

• Clean and sloped. A sloped surface doesn't hold rainwater; a ragged surface stays open much longer.
• No stubs. A piece of branch left hanging doesn't heal: it dries out and becomes an entry point.
• No flush cuts. Cutting flush with the parent branch removes the collar, the very tissue that closes the wound.
• Disinfected tools. This is the point almost nobody respects and the one that costs the most. Olive knot (Pseudomonas savastanoi) is transmitted through cuts, and the main vector is the blade passing from one tree to the next. A spray bottle of disinfectant in your pocket and a wipe of the blade between trees — especially if you've seen galls on the branches — is the single most effective preventive measure.
• After heavy pruning, many olive growers spray a propolis-based product on the largest wounds. It's cheap and it helps.

The six mistakes that cost you the harvest

1. Pruning in August, or in frost. In August you remove next year's flower buds; with a hard frost on the way, fresh wounds pay the price. Outside those two cases, the whole winter is good.
2. Restoring an abandoned tree all at once. A drastic cut on an olive neglected for years won't bring it back into production: it stresses it and fills it with water sprouts that you'll have to remove again the following year. Renewal pruning should be spread over 2-3 years.
3. Not disinfecting the blades. A healthy grove infected by a sick tree is damage you carry for years.
4. Removing hanging branches. It looks tidy, it's lost production.
5. Leaving the centre of the canopy closed. Less light, fewer olives, more damp, more disease.
6. Skipping a year "because it's loaded anyway". The olive naturally tends towards alternate bearing: one full year and one light year. Annual production pruning is precisely what smooths out this seesaw. If you skip the heavy years, alternate bearing gets worse.

What to cut with, in practice

Olive pruning combines three different types of cut, and the reason so many people tire halfway through the day is that they try to do them all with the same tool.

Branches up to 3-4 cm. This is 80% of the work: renewing fruiting shoots, woody water sprouts, thinning inside the canopy. Here professional electronic shears change your day, not so much for speed as for your hands: a mature olive tree means hundreds of cuts, and by hand your wrist gives out long before the tree does. On olive trees it pays to go for generous cutting capacity — a Swansoft PRU-45 PLUS reaches 45 mm and saves you changing tools every two branches.

Limbs and old wood over 5 cm. Here you need a cordless chain pruner: in renewal pruning, where you have to take down whole limbs, a Swansoft CS-2 8" makes in a few seconds a cut that would cost you five minutes and your back with a bow saw.

Top of the canopy. If the tree has grown beyond a comfortable size, the choice is between a ladder and a pole. A pole pruner on a telescopic pole lets you work from the ground: safer, and above all it lets you see the canopy from outside while you cut, which is exactly the right point of view to understand where to open it up.

Whatever tool you use, a sharp blade matters more than power. A blade that crushes instead of cutting leaves ragged wounds that heal badly, and on an electric tool it wastes battery and motor. A sharpening pass every half day of work is time gained.

In short

• Winter pruning from early December, as soon as the harvest closes: December-March in the South and Centre, late February-April in the North and at altitude.
• Never in August, and never with a hard frost on the way.
• Light green pruning in June-July for water sprouts and suckers.
• Olives grow on the previous year's shoots: renew, don't empty.
• Clean, sloped cuts, no stubs, disinfected blades between trees.
• Abandoned trees: restore over 2-3 years, never in one season.

If you're unsure which tool can handle your type of olive grove — young trees in rows or centuries-old trees with a wide vase — write to us: we'll tell you what you really need and what you don't.