Olive Tree in a Heatwave: Does It Really Need Watering?
Here is the received idea that needs correcting: an established olive tree in open ground hardly needs watering at all, even in a heatwave. It is one of the most drought-resistant trees there is, and excess water is more fatal to it than a lack of it. Only young trees (1 to 3 years) and potted olive trees call for regular watering. This guide settles a recurring question from our Orchard and Citrus section.
The Chatelain Method: frugality first
We observe the age and the growing mode (open ground or pot); we diagnose the real need, usually overestimated; we correct with sparing watering; we prevent root rot with impeccable drainage.
Why the olive tree copes with heatwaves
The olive is the Mediterranean tree par excellence: leathery foliage, deep roots, a frugal metabolism. A well-rooted tree draws water from deep in the soil and sails through weeks of heat without damage. It is the exact opposite of the potted lemon tree, thirsty and drought-sensitive.
The Chatelain’s rule of thumb. On an olive tree in open ground, yellowing leaves combined with waterlogged soil do not signal thirst but drowning: excess water and the beginnings of root rot. The reflex « it’s hot, I’ll water » is, here, the surest way to weaken it.
Should you water? The table by situation
| Situation | Need during a heatwave |
|---|---|
| Established olive tree, open ground | Almost none; at most one generous watering per month in intense heat |
| Young olive tree (1-3 years), open ground | 10 to 15 L, once or twice a week |
| Potted olive tree | 3 to 5 L, 2 to 3 times a week; more often for a small pot in full sun |
Adjust these benchmarks to soil and exposure. In extreme drought, a mature tree can be supported with one deep monthly watering to preserve fruiting — but never with frequent, shallow doses.
Telling excess from lack of water
The trap is that both show up as yellowing leaves. You tell them apart by the soil and the roots:
- Excess water: waterlogged soil, soft yellow leaves, sometimes a rotting smell at the base, stalled growth. This is danger number one, especially in pots.
- Real lack of water: soil hardened and dry at depth, leaves curling and greying — rare on an established tree, possible on a young tree or in a pot.
The right routine for a potted olive tree
This is where vigilance matters, because a pot dries fast yet drains poorly if badly designed. Let the mix dry partially between waterings, water in the morning or evening until it runs out of the drainage holes, and always empty the saucer: standing water rots the roots. For the container and substrate, see large planters for trees. For the general summer watering method, see watering in a heatwave.
Mistakes to avoid
- Watering a mature olive tree « because it’s hot »: you drown it for nothing.
- Leaving a full saucer under a pot: guaranteed rot.
- A non-draining substrate in a pot: water stagnates and suffocates the roots.
- Pruning or fertilising in the middle of a heatwave: needless stress for a naturally frugal tree.
FAQ
Should you water an olive tree during a heatwave?
An established olive tree in open ground, no: it withstands drought very well. At most, one generous watering per month in intense heat. Young trees and potted trees, however, need regular but measured watering.
My olive tree is yellowing in summer — does it lack water?
Not necessarily; it is often the opposite. Yellowing with waterlogged soil signals excess water and the start of root rot. Check soil moisture at depth before watering any further.
How often should a potted olive tree be watered in very hot weather?
About 2 to 3 times a week, with 3 to 5 litres, letting the mix dry partially between waterings and emptying the saucer. A small pot in full sun may ask for a little more.
Does the olive tree handle heat better than the lemon tree?
Yes, clearly. The olive is adapted to Mediterranean drought, while the lemon tree is thirsty and copes poorly with long dry spells, especially in a pot.
Sources and further reading
- Jardiland — watering an olive tree well
- Jardins de France — gardens and heatwaves
- Aujardin.info — the olive tree
- Back to Orchard and Citrus
Written and verified by the editorial team at Les Jardins d’un Chatelain.