Cherry Tree Calendar

January — Dormancy and inspection

What to do

• Look the tree over before thinking about anything else: for wounds and cracks, dry twigs, mummified fruit, and suspicious damage to the bark and wood.
• Take down any mummified fruit still on the tree.
• Don't prune hard just because the tree is dormant: in cherries, pruning needs thought.

Why

Mummified fruit and diseased twigs are where brown rot overwinters. Heavy winter pruning leaves wounds that bacterial canker can enter.

Common mistakes

• Heavy winter pruning.
• Leaving mummified fruit on the tree.

February — Pre-spring sanitation

What to do

• If you must prune, do it in dry weather and as late in dormancy as you can: wounds made early in dormancy are far more susceptible to infection.
• Cut out twigs killed by brown rot and carry them out of the garden. Remove shriveled fruit before bud break as well.
• Clean your tools between cuts.

Why

The brown rot fungus overwinters in mummified fruit and diseased twigs. The more you remove now, the less inoculum there is at bloom.

Common mistakes

• Pruning in cold, wet weather.
• Leaving the cut branches under the tree.

March — Bud swell

What to do

• Watch the weather and infection risk, not just the calendar.
• Keep track of rainy periods: infecting blossoms takes a few hours of wetness.
• Look for damage and dry twigs that appeared over winter.

Why

At around 20–25°C (about 70–75°F) a blossom needs roughly 3 hours of wetness to become infected, and at cooler temperatures at least 6 hours. That is why rain at the start of bloom is the signal we watch.

Common mistakes

• Acting by date instead of risk.
• Ignoring rainy periods.

April — Bloom

What to do

• This is one of the most important moments. Pay particular attention to brown rot on blossoms and shoots.
• Wet weather during bloom means higher risk. Watch for blossoms and twig tips that turn brown and wilt.
• Protect the bees: during active bloom, do nothing "just in case". Pollinators are part of the coming crop.
• Keep the canopy open so it dries faster.

Why

Infection of the blossoms during bloom develops quickly in rain. One missed stage can mean withered blossoms.

Common mistakes

• Unnecessary interventions during bloom.
• Overlooking a rainy bloom.

May — After bloom

What to do

• Protecting the young fruit starts now. Look over the leaves for spots and the young fruit for damage.
• Watch for pests and keep track of rainfall and long periods of leaf wetness.
• Hang yellow sticky traps for cherry fruit fly before the fruit ripens (timing depends on your region and season), on the sunny side of the tree, in the upper canopy. Clear fruit and foliage around them.
• In a wet spring, keep watching and remove infected twigs in dry weather.

Why

A yellow sticky trap helps you see when the adult flies appear and fly. It is a better investment than any "just in case".

Common mistakes

• Leaving traps unchecked.
• Stopping observation after bloom.

June — Ripening and harvest

What to do

• Check traps once a week and record catches. Replace them every 3–4 weeks or when they are covered with debris.
• Pick when the fruit is ripe, and set aside damaged and wormy fruit.
• In rainy weather, watch for fruit rot.
• Carry away harvest waste: debris around the tree keeps the fly population up.

Why

Sanitation after harvest reduces cherry fruit fly populations, and high populations are much harder to control.

Common mistakes

• Leaving wormy cherries under the tree.
• Picking in rain without checking for rot.

July — After harvest

What to do

• The season isn't over. Look over the leaf mass.
• If leaf spots are heavy and leaves drop early, the tree can go into winter weakened.
• If pruning is needed, do it in summer after harvest, in dry weather, so the wounds stay dry for 2–3 weeks.
• Collect fallen and rotten fruit.

Why

Healthy leaves after harvest keep working for the tree and build reserves for next season. Summer wounds are far less susceptible to bacterial canker than winter ones.

Common mistakes

• Neglecting the tree after harvest.
• Summer pruning in rainy weather.

August — The leaves are working

What to do

• Keep watching the leaves for spots and early leaf drop.
• Pruning cherries, if needed, is safest in August, when the risk of bacterial infection is lower.
• Water deeply in dry spells rather than a little every day.

Why

For susceptible varieties, summer pruning in dry conditions is recommended. Healthy leaf mass is the foundation of a good crop next year.

Common mistakes

• Heavy pruning in wet weather.
• Neglecting water in drought.

September — Before autumn

What to do

• Look over the leaves for spots and early leaf drop.
• Collect fallen fruit and leaves if you haven't already.
• Write down what happened this season: which problems you had and when.

Why

Heavy early leaf drop weakens the tree before winter. Your notes show which stages were risky.

Common mistakes

• Leaving infected leaves under the tree.

October — Autumn sanitation

This month

What to do

• Start with sanitation: collect the remaining mummified fruit.
• Look for dry and diseased twigs and remove them in dry weather.
• Deal with heavily infected plant debris — don't leave it under the tree.

Why

Mummified fruit and diseased twigs are the main overwintering source of brown rot. Sanitation is the cheapest prevention there is.

Common mistakes

• Leaving mummified fruit.
• Pruning in cold, wet autumn weather.

November — Before winter

What to do

• Check the trunk and main limbs for wounds, cracks, and cankers.
• Clean and put away your tools.
• Don't prune hard: wounds made early in dormancy are the most susceptible to infection.

Why

Wounds made early in dormancy are much more susceptible to bacterial canker than those made late in it.

Common mistakes

• Heavy pruning in late autumn.

December — Dormancy and review

What to do

• Go over your season notes: which problems you had, when they started, and what the result was.
• Plan the sanitation check and the carefully considered pruning for late winter.

Why

The scheme is simple: autumn — sanitation; winter — inspection and sensible pruning; early spring — watching the weather and infection risk; bloom — attention to brown rot and pollinators; after bloom — protecting leaves and young fruit according to risk; before ripening — monitoring for cherry fruit fly; after harvest — keeping the leaf mass and lowering the infection load.