Pruning stone fruit: sweet cherry, apricot, and mirabelle after harvest

Stone fruit is the family where winter pruning does the most damage. Many gardeners prune cherries, plums, and apricots in February along with the apples, simply because the saw is already in hand. You often only see the result years later: a branch with silvery, shimmering leaves, wounds gummed shut with resin, an apricot that suddenly wilts in May.

This article covers three stone fruit species that haven't gotten much space in the magazine so far: sweet cherry, apricot, and mirabelle along with its sister, the greengage. For sour cherry, European plum, and peach there are dedicated guides.

Why stone fruit needs summer

A fruit tree seals off wounds rather than healing them. The cambium under the bark pushes a callus ridge over the cut surface, and barrier layers form in the wood against fungi. In July this happens within a few weeks, in January it doesn't happen at all.

With stone fruit, two more opponents join in, and they're active exactly during the cold season. Silver leaf (Chondrostereum purpureum) is a fungus that spreads its spores in damp weather from autumn to spring and enters through fresh wounds. Infected branches get silvery, shimmering leaves and gradually die back. Bacterial canker (Pseudomonas syringae) also exploits wounds and frost cracks in winter, causing bark to sink in and branches to wilt.

Sweet cherry: spare the bouquet spurs

Sweet cherry (Prunus avium) is the most vigorous tree in the orchard. On a seedling rootstock it grows ten to fifteen meters tall, and it has strong apical dominance. Without pruning, after ten years the fruit hangs at a height only the starlings can reach.

Cherries sit on bouquet spurs: small, stubby short shoots on two-year and older wood, where the flower buds cluster as densely as a bouquet. These bouquet spurs fruit for several years. You keep them by not constantly shortening the main branches, but instead removing whole branches or cutting back to a lateral.

1. Prune right after harvest

   As soon as the last cherries are picked, you can see exactly which branches fruited and which only grew leaves. Depending on the variety, the window runs from late June to late July.

2. Limit height by cutting back to a lateral

   If the tree is too tall, cut the central leader and the highest main branches back to a lower, outward growing side branch. Topping without a leading side branch just gets you a broom of water sprouts.

3. Remove competing and upright shoots

   Remove shoots that grow parallel to the main branch or steeply into the interior, cutting them off at the base. The crown should stay open and built up in tiers.

4. Renew drooping, worn-out wood

   Branches that, after many years, hang down and have hardly any bouquet spurs left, you cut back to a younger, well-placed shoot.

Sweet cherry ‘Hedelfinger’ is an example of an old, strongly growing variety that, on seedling rootstock without regular summer pruning, quickly grows over the roofline. On weak rootstocks like GiSelA 5 the same variety stays at three to four meters. How rootstock and pollinator relate to each other is covered in Planting sweet cherry, and how harvest and summer pruning work together, in Cherry harvest and summer pruning.

If you only have room for a narrow tree, a columnar cherry works well. It fruits on short shoots right along the trunk, and pruning it comes down to shortening side shoots that have grown too long, after harvest, to about a hand's width.

Apricot: the most sensitive stone fruit

Apricot (Prunus armeniaca) fruits on one-year-old long shoots and on short spurs that bear fruit for two to three years before wearing out. Its pruning has to do both jobs: stimulate new shoots every year and replace old fruiting wood.

At the same time, it's the most sensitive stone fruit. The dreaded apricot dieback, where whole branches suddenly wilt in early summer, has many causes, but large wounds and frost cracks are among the most important entry points. That's why you make large cuts on apricot only after harvest, in dry weather, and never more than two or three at once.

Mirabelle and greengage: thin out, don't shorten

Mirabelles (Prunus domestica subsp. syriaca) and greengages (Prunus domestica subsp. italica) are plum relatives and, like plums, fruit on two- to three-year-old wood and on short fruiting spurs. Both naturally form a round, fairly open crown and need less pruning than European plum.

Mirabelle is the least demanding of the two. A thinning cut every two years after harvest is enough: take out crossing and inward growing branches, thin out crowded areas. Greengages grow bushier and denser. Here you thin every year, otherwise the crown stays wet for a long time after rain, and brown rot has an easy time of it.

Mirabelle ‘Nancy’ is considered the classic variety with the finest flavor. Its small fruits sit densely on short shoots, which you leave in place when thinning. If you're still unsure about the difference between mirabelle, greengage, plum, and European plum, you'll find it explained in European plum, plum, mirabelle, greengage: who's who.

Avoiding large wounds

With stone fruit, more than with any other fruit: prune branches while they're still young. A shoot that you spot as competition in its second year and remove leaves a wound about one centimeter across. The same branch ten years later leaves a wound of ten centimeters, and on a cherry that never fully heals.

If you do have to remove a thick branch, do it in high summer, in dry weather, cleanly at the branch collar and with a three-cut method, so the bark doesn't tear. How that's done is shown in Tools for pruning fruit trees.

Put the end of harvest into your calendar as a reminder to prune. In the Gartenkern diary, the cherry harvest becomes the yearly signal to pick up the saw, and over the years you can see how each branch responded.

Frequently asked questions

When should you prune a sweet cherry tree?

Right after harvest, from late June to late July depending on the variety. That way wounds heal quickly, and silver leaf and bacterial canker barely stand a chance. You shouldn't prune cherries in winter.

How do I make a cherry tree that's grown too tall shorter?

Over several summers, by cutting back to a lateral. You cut the central leader and the highest branches off just above a lower, outward growing side branch. Remove no more than a quarter of the crown per year, otherwise the tree responds with a mass of water sprouts.

When should you prune an apricot tree?

After harvest, from late July to mid August, or during flowering in spring. Make large cuts on apricot only in dry weather and no more than two or three at once, because it reacts sensitively to wounds.

Do you need to prune a mirabelle tree?

Only a little. A thinning cut every two years after harvest is enough. In it, you remove crossing, inward growing, and dead branches. You leave the short fruiting shoots in place.

What helps with gummosis on a cherry tree?

Gummosis is a stress response. Avoid large wounds and winter pruning, make sure the soil drains well, and protect the trunk in winter with a white wash against frost cracks. If resin keeps oozing from one spot and the bark sinks in, cut the branch back into healthy wood in summer.