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 "at the end of winter". The useful answer is a bit longer, 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 at risk and not working

The olive is an evergreen and never goes fully dormant like an apple tree. This changes everything. The right window for winter pruning is when two conditions meet:

• the risk of hard frost has passed — the olive suffers a lot from cold, and a tree freshly opened up by cuts suffers even more;
• spring growth has not started yet — cutting once budding is under way means throwing away energy the tree has already spent.

Between these two conditions lies the window. It is narrow, and it shifts with latitude and altitude.

The calendar, region by region

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

From late February to late March. In the mildest coastal areas you can start as early as late February. It's the longest window in Italy: use it to spread the work out rather than cramming it into two weekends.

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

From March to early April. The classic mistake here is starting too early, taking advantage of a sunny week in February: then the cold comes back and the fresh cuts pay the price.

North and inland high areas

From late March to late April, and in some cases even the first week of May at altitude. Better late than frozen.

The practical rule that works everywhere: look at the local almond and peach trees. When they have been in bloom for a while and night temperatures are steadily above zero, the olive window is open.

Why you don't prune in autumn (even if it seems convenient)

Harvest ends between October and December, the tools are already in the field, and the temptation to prune straight afterwards is very strong. It's by far the most common mistake.

A cut made in November stays open all winter: rain, damp and cold work on the wound for months before the tree has the strength to heal it. On top of that, you remove the canopy the tree needs as thermal protection just as the cold arrives. People who prune in autumn notice it two years later, when production drops and the old branches haven't been replaced.

The same goes for 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 autumn or August. Explained above: wounds exposed to winter, or flower buds removed.
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 at the end of winter: late February-March in the South, March-early April in the Centre, April in the North.
• Never in autumn right after harvest, never in August.
• 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.