Gadenin日本語Get the appPrune for height and light, not for shape
An unpruned avocado goes up, not out, and takes its fruit with it. The whole purpose of pruning a garden tree is to keep the fruiting wood within reach and to let enough light into the canopy that the lower branches keep their leaves. Fussy structural pruning of the sort apple trees get is wasted here; the tree fruits on the outside of the canopy on wood grown the previous season, so anything that keeps a broad, well-lit outer surface at a height you can reach is doing the job.
Start early and keep it small. A tree topped at ten or twelve feet (3-3.5 m) every year, with a few whole limbs removed to open the middle, stays productive and safe to work. A tree left alone for a decade and then cut back hard responds with a thicket of vertical water shoots, sunburnt limbs, and two or three years without a crop.
When to cut
Prune after the risk of frost has passed and before or just after the main flush of flowering, so the cuts heal in warm weather and the tree has the whole season to grow new canopy over the exposed wood. Avoid pruning in late autumn: the soft regrowth it forces is the first thing to be killed by cold, and open cuts in cool damp weather invite dieback.
| Season | What to do | Why |
|---|---|---|
| Late winter, before growth | Nothing on a cold-exposed tree; wait | Cuts stay open in cold weather and the tree cannot cover them |
| Spring, after frost risk | Height reduction, limb removal, opening the center | Warm weather heals the cuts and regrowth shades the exposed bark |
| Summer | Light tipping, removing broken or shaded-out wood | Small cuts only; the canopy is carrying fruit |
| Autumn | Only damaged wood | New growth forced now will be frost-killed |
Exposed bark burns within days
Avocado bark has almost no tolerance for direct sun. Remove a large limb and the wood beneath it, previously shaded for years, can be scorched within a week of hot weather: the bark cracks, the cambium dies in patches, and those patches never recover. Sunburnt limbs are a permanent loss and an open door for wood-boring insects and canker.
So protect every surface you expose. Paint newly bared trunks and upper limb surfaces with white water-based paint diluted by half with water, immediately after pruning and before the next hot spell, and repeat as the coating weathers. This is standard practice, not a precaution for extreme climates, and it is the reason to prune in stages rather than opening a whole canopy at once.
Never remove more than about a quarter of the canopy in one season, and never strip the interior in a single pass. Take a large tree down over two or three years and the tree grows its own shade to keep up with you.
What to cut, in order
Work through the tree in a fixed order and stop when you have taken enough. Most of the value is in the first two steps.
- Anything dead, broken or crossing Take these out first at their point of origin. Removing them costs the tree nothing and often reveals that the canopy is already open enough.
- Shoots growing from below the graft union On a grafted tree, any shoot arising below the swollen graft joint or straight from the ground belongs to the rootstock, not to the fruiting variety. Rub or cut these off flush as soon as you see them. Left alone they are vigorous, they steal the tree's energy, and they will never bear the fruit you bought.
- One or two whole limbs to open the center Rather than shortening many branches, remove one or two entire vertical limbs back to their origin. This lets light into the interior without triggering the mass of water shoots that heading cuts produce.
- Height, taken at a side branch Reduce tall leaders by cutting back to a well-placed outward-growing side branch at the height you want, rather than sawing off a stub. A cut into a side branch redirects growth; a stub produces a broom of upright shoots.
- Tip the outer growth lightly Shortening long new shoots by a few inches on the outside of the canopy encourages branching and keeps fruiting wood close to the frame. Keep this light, since the outer wood is where next season's flowers come from.
Seedlings, stakes and the young tree
A tree grown from a stone runs up as a single unbranched whip and needs different treatment from a grafted plant. Pinching the tip when it reaches about twelve inches (30 cm), and again on the resulting shoots, forces branching and keeps it a manageable plant rather than a pole. Understand that this shapes the plant but does not bring flowering forward; a seedling flowers when its wood matures, and nothing you do with the pruners changes that.
On a young grafted tree, resist the urge to tidy. Leave the low branches for the first few years even where they look untidy, because they shade the trunk, feed the developing root system and build trunk calliper. Remove them gradually as the canopy above grows large enough to shade the trunk on its own.
Finally, note what you cut and when. A short line each spring recording how much you took off and how the tree responded is worth more than any general rule, because avocados differ enormously in vigor and yours will teach you its own habit within three seasons.