Plum Tree Calendar

A plum is a rewarding tree, but it needs three things on time: pruning in late winter, thinning the fruit when the tree sets too much, and picking just as the fruit softens. This calendar explains what to do each month and why. Timings are for a temperate climate and follow the condition of the tree and the weather, not only the date. The calendar names no spray products: for plant protection, always follow the product label and the advice of a local agronomist.

At a glance

Types: European plums (prune plums, gages) and Japanese plums — they differ in tree shape, pollination and how much thinning they need.
Pollination: Most European plums set fruit on their own but crop better with another variety nearby. Japanese plums need a pollinator.
Planting: In well-drained soil; plums do not tolerate wet, heavy ground. About 5.5–6.5 m (18–21 ft) between trees.
Pruning: Late winter or early spring. Summer pruning of vigorous inner shoots in late June or early July.
Where fruit forms: Mostly on short fruiting spurs on 2- to 5-year-old wood.
Thinning: After the risk of frost has passed, once the fruit is visible: about 10–15 cm (4–6 in) apart on a heavy set.
Harvest: Usually late summer to early autumn, depending on the variety — when the fruit softens and changes colour.
Main risks: Plum pox / sharka (a virus, no cure), plum fruit moth, brown rot, aphids.

January — Dormancy and inspection

What to do

Look the tree over for broken, dead and diseased branches and for small bark cankers with gum.
Clean and sharpen pruners and saw.
Plan the pruning: which branches crowd the crown and which grow inward.

Why

Pruning comes in late winter, but looking now tells you what to cut when the time comes.

Common mistakes

Pruning in hard frost.

February — Late-winter pruning

What to do

Prune in late winter, on days without hard frost, before the tree wakes up.
First remove dead, diseased and broken branches, then thin crowded and inward-growing ones.
On an established tree, remove about a quarter of the branches; remove root suckers regularly.
Do not just clip the tips — plums fruit on short spurs on 2- to 5-year-old wood.
Take diseased prunings out of the garden.

Why

An open crown lets light reach the fruiting spurs and dries faster after rain, which reduces disease.

Common mistakes

Autumn pruning that triggers late growth.
Clipping every tip.

Tip: European plums are usually trained to a central leader with 4–5 scaffold branches; Japanese plums to an open vase with 3–4 main branches.

March — Planting and finishing pruning

What to do

Finish pruning if you did not get to it in February.
Plant new trees in well-drained soil, about 5.5–6.5 m (18–21 ft) apart, not in lawn.
If the variety needs a pollinator (Japanese plums always do), plant a suitable variety nearby.
When planting bare-root trees, keep the graft union 5–10 cm (2–4 in) above the soil.

Why

A tree planted while dormant roots in before the heat. Plums do not tolerate wet, heavy soil.

Common mistakes

Planting too deep or too shallow.
Planting in a waterlogged spot.

April — Bloom

What to do

Watch the forecast for late frost during bloom.
Water young trees about twice a week in their first season, around the root zone rather than over the leaves.
Do not fertilise newly planted trees in their first year.

Why

Blossoms are sensitive to frost. A young tree needs water but not fertiliser while it establishes.

Common mistakes

Fertilising in the planting year.
Wetting the leaves when watering.

May — Fruit thinning

What to do

Once the risk of frost has passed and the fruit is visible, thin a heavy set to about 10–15 cm (4–6 in) apart.
Remove damaged fruit first, then fruit at the branch tips, and break up clusters.
Thin Japanese plums almost always; European plums mainly on a very heavy set.
Check the leaves for curling and aphids.
Look for pale rings and blotches on the leaves and sunken spots or deformities on the fruit: this can be plum pox (sharka). It is a virus spread by aphids and infected nursery stock, and it cannot be cured — ask an agronomist.

Why

The earlier you thin, the larger the fruit. An overloaded tree gives small fruit and can break its own branches.

Common mistakes

Leaving all the fruit.
Thinning too late.

June — Summer pruning and watering

What to do

In late June, remove vigorous upright shoots in the centre of the crown to let in light and air.
Water established trees about every two weeks in drought, deeply enough to wet the soil to 30–60 cm (1–2 ft).
Watch for holes in the leaves and gum on the bark.
Watch for wormy plums — the plum fruit moth is a key pest in many regions. Pheromone traps show when the flight starts, as with codling moth on apple.

Why

Summer pruning of inner shoots keeps the crown light without triggering the vigorous regrowth of winter pruning.

Common mistakes

Pruning the whole tree hard in summer.

July — Early varieties and propping branches

What to do

Prop up branches that are heavily loaded with fruit.
Pick early varieties when they soften and change colour — often over several pickings.
Finish summer pruning of inner shoots if you did not get to it in June.

Why

A heavy crop can break branches. Early varieties do not ripen all at once.

Common mistakes

Picking hard, green fruit.

August — Harvest

What to do

Pick when the fruit softens and changes from green to blue, purple or red depending on the variety.
Nearly ripe fruit can finish ripening at room temperature.
Refrigerate only ripe fruit; use within about three weeks.
Collect fallen and rotting fruit under the tree.

Why

Rotting fruit under the tree and on the branches spreads disease and attracts wasps.

Common mistakes

Leaving rotting fruit under the tree.
Refrigerating unripe plums.

September — Late varieties

What to do

Pick late varieties — they often ripen almost all at once.
Remove mummified fruit from the branches.
Note which branches cropped best and where problems appeared.

Why

Mummified fruit left on the tree carries disease into the next year.

Common mistakes

Leaving dried fruit on the branches.

October — Autumn clean-up

What to do

Collect fallen leaves with spots and holes and take them out of the garden.
Do not prune now — autumn pruning can trigger late growth.
Cut tall grass back from the trunk.

Why

Diseased leaves under the tree carry the disease into the next spring; a clear area around the trunk protects the bark.

Common mistakes

Pruning in autumn.

November — Dormant planting and planning

This month

What to do

If the soil is not frozen and drains well, you can plant new dormant trees.
Choose the variety and a pollinator before you buy.
Buy certified planting material and prefer varieties more tolerant of plum pox — the disease also spreads with infected young trees.
If you do not know your soil, have it tested before planting.

Why

The right variety and pollinator decide the crop for years to come.

Common mistakes

Buying a Japanese plum without a suitable pollinator.

December — Season review

What to do

Write down when the plum bloomed, whether there was frost, how much it set and how much you picked.
Note when holes in the leaves, gum or leaf curl appeared.
Get tools ready for pruning in late winter.

Why

Your own notes are the most accurate calendar — they show what really happens in your garden.

Common questions

When should plum trees be pruned?

In late winter or early spring. Pruning in late summer and autumn can trigger late growth that does not harden before the cold, so it is avoided. In summer — late June or early July — you can remove vigorous shoots in the centre of the crown to let light in.

How much should I prune a plum tree?

First remove dead, diseased and broken branches. On an established tree, take out about a quarter of the branches, thinning crowded ones and those growing inward. Plums fruit mainly on short spurs on 2- to 5-year-old wood, so do not just clip the tips.

Should plum fruit be thinned?

If the tree has set heavily, yes. Japanese plums almost always set more than they can size, and without thinning the fruit stays small. European plums mainly need thinning on a very heavy set. Thin early, after the risk of frost, to about 10–15 cm (4–6 in) between fruits; the earlier you thin, the larger they grow.

How do I know when plums are ripe?

The fruit softens and changes colour from green to blue, purple or red depending on the variety, while green varieties take on a yellowish tint. Early varieties are often picked several times over a few weeks; late varieties tend to ripen almost all at once.

How should plums be stored?

Nearly ripe fruit finishes ripening at room temperature. Put plums in the refrigerator only once they are ripe, and use them within about three weeks.

What causes holes in plum leaves?

Round spots with a purplish tinge that darken and drop out, leaving holes, are typical of shot hole disease of stone fruit. It can also cause dark spots on the fruit and dark lesions on twigs. Collect fallen diseased leaves and ask a local agronomist about protection.

Why is gum oozing from my plum tree’s bark?

Amber, sticky gum oozing from wounds or small cankers in the bark is often a sign of bark canker (fungal or bacterial). It may come with sudden wilting of leaves and darkened bark. Cut affected branches back to healthy wood and protect the tree from injuries.

Why do plum leaves curl in spring?

Most often because of aphids — the leaves curl and distort and are sometimes sticky. Usually no action is needed unless about half of the leaves are affected and live aphids are present; their natural enemies often deal with them.

Important: This calendar is a general growing frame and does not replace an on-site look or an agronomist's advice. It names no spray products. For crop protection, always follow the product label and the rules in force.

Sources

This calendar was checked against the public references below. It is general background, not a diagnosis of a specific plant.

Last reviewed: 3 November 2026

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