Many sweet cherry trees require a great deal of space, so unless you have a large garden, look for a cherry tree grafted onto a dwarfing rootstock. Older varieties must be cross-pollinated by another variety; if you have space for only one tree, choose one of the newer, self-fertile cultivars. You can grow sour ‘Morello’ cherries, used mainly for bottling and jam-making, as a tree or a fan-trained espalier. Self-fertile, they grow well in cool conditions.
Choosing a cherry tree
Considerable progress has been made in the breeding of high-quality tropical cherries suited to warm climates, but most varieties available commercially require a cool to cold winter. They are usually grown as shaped trees. Dwarfing stocks are commonly used to ensure that the trees grow to a manageable height and spread, and are easy to care for and to harvest. In cool-climate areas they are sometimes shaped into ornamental espaliers and grown against north-facing brick walls to receive the reradiated warmth.
The two distinct types of cherry – sweet and sour (acid) – derive from British Prunus avium and P. cerasus and also forms brought from eastern Europe by the Romans. Self-fertile varieties include:
Lapins – Red skin and flesh; firm, juicy; can be very large; excellent flavour.
Morello – Sour cherry, usually the only one available.
Stella – Huge, dark red, fleshy fruits; midseason.
Sunburst – Large, round fruits with red skin and flesh; superb flavour.
Sweetheart – Sweet, red, firm fruits with good flavour; very late.
Many older varieties, grown for their flavour and texture, are still very popular. They include:
Bing (midseason) and Ron’s Seedling.
More recently bred varieties, which must be grown with a cross-pollinating variety, include:
Merchant Dark – skin and flesh; large, sweet fruits with excellent flavour; early; a universal pollinator.
Rainier – Large; white-fleshed; gold skin blushed pink; very sweet; high quality.
Sylvia – Large, dark red fruits; good quality and flavour; compact growth.
In cool-winter areas some superbly flavoured heirlooms are still grown – Carnation, May Duke, Napoleon, Old Black Heart and White Heart.
A deep, well-drained soil in sun gives the best results with sweet cherries, but aspect is unimportant for sour cherries. Good soil preparation will repay you handsomely, however. Allow a diameter of 1.5 m for each tree and dig in generous amounts of compost, rock dusts such as basalt, granite and rock phosphate, and wood ashes. Plant bare-rooted trees from late winter to spring. Pot-grown trees may be planted at any time of year as long as the weather is suitable. When planting a bush tree, drive a supporting stake into the hole and tie the tree to it. Unless the tree is secured in this way, it will have a tendency to be rocked by high winds, and this will lead to the loosening of the roots and a delay in the tree’s development. Water very thoroughly initially. Apply a pelleted slow-release organic fertiliser each year in early spring. Water the ground under trees thoroughly during summer dry spells.
Pruning sweet cherries – Limit the pruning of standard sweet cherry trees to the removal of dead or diseased branches as well as branches that rub against one another. Do this in autumn, after harvesting has finished. Paint the cut ends with a proprietary sealing compound to keep out silver leaf infection. Sweet cherries can also be trained as fan-shaped espaliers.
Pruning sour cherries – For the first three years, train sour Morello cherry trees in the same way as bush apples. Alternatively, shape them as fan-trained espaliers. Established sour cherry trees fruit only on wood that developed during the previous summer. Your objective is to stimulate plenty of new growth each year by heavy feeding and by pruning to produce renewal shoots. After fruiting, cut out some of the less productive branches on bush trees, but leave those that are more than three years old; if you cut them, the wound would be too severe. Seal all cuts with a wound healant to prevent disease spores entering the vulnerable, freshly cut surfaces.
Pests and diseases
Birds love cherries – especially sweet varieties – so you’ll probably have to net the tree. If the tree is very large, you can keep at least some of the fruit safe by netting the lower branches. Trees on dwarfing rootstocks are easier to cover completely. The other pests most likely to attack cherries are caterpillars and aphids. The diseases are bacterial canker, chlorosis, honey fungus (not in South Africa), shothole and silver leaf.
Harvesting and storing
Harvest sweet cherries in summer. They can be pulled off by hand. They do not keep well and should be eaten soon after picking. Sour cherries, such as Morello, mature from summer to mid-autumn. Pulling them off can wound the spurs and allow the diseases to which the trees are susceptible to enter. Avoid this by cutting off the cherry bunches with sharp scissors.