CHERRY BACKGROUND

Cherries tend to be vigorous trees, but can be fan trained against a wall with careful pruning. It is not advisable to espalier or cordon them, or constrain their growth to too small a space, because they do not like regular close pruning, as this tends to cause sap bleeding and admit disease. They all have wonderful blossom in spring.

It must be borne in mind that, apart from some 'Duke' cherries, which are a cross between sour and sweet cherries, none of the dessert (sweet) varieties are fully self-fertile and a single cherry tree is unlikely to set fruit without another nearby. As with other fruit, pollinators have to flower at the same time. Also, some cherries are incompatible pollinators with others, quite apart from flowering time. Cherries fall into groups of mutually incompatible pollinators, but the collection of data is very incomplete. The situation is partly helped by a few cherries being universal pollinators, pollinating any other cherry that flowers at the same time. Otherwise, one has to select pollinators which are known to be in another incompatibility group, and which also flower at a similar time. It is confusing but we give a guide to suitable pollinators below. Avoid the same incompatability group and choose from the same or adjacent flowering time. Use a universal pollinator if needed.
Cherries are grafted onto Colt (semi-dwarf) rootstocks, or equivalents like Pi-Ku, or dwarfing Gisela 5. Colt can still give quite large trees – up to 20ft – if unpruned.