Perfect PLUMS

RHS Chief Horticulturist Guy Barter shares his how-to on perfecting plum growing

- Guy Barter

European plums, Prunus domestica, arose in the Caucasus mountains near the Caspian Sea as a natural hybrid of sloes (Prunus spinosa) and cherry plum (Prunus cerasifera). People have been enjoying their sumptuous fruits for over 2,000 years.

Plums are exceptionally diverse in colour, size and shape, but fit into five main groups: ‘greengages’, very sweet, green to golden in colour, round in shape; ‘prunes’, oval and purple used for drying; yellow or red ‘egg-shaped plums’ used for jam and canning; the ‘Victoria’ or ‘Lombard’ plums’ which are standard garden plums; and ‘gage-plums’ which combine something of the flavour or gages with the larger fruits of plums.

CULTIVATION

Plums tolerate a wide range of soils including clay soils, but will not thrive where waterlogging occurs. Sheltering from wind aids pollination and limits mature fruit loss and branch breakage in summer, but they do poorly if shaded.

Although very hardy, plums flower early and their blossom is vulnerable to frost damage. Where late frosts are likely consider wall or fence cultivation to fend off the worst of the frost, and apply fleece protection on chilly nights.

Unfortunately, the very dwarfing rootstocks that make some fruit trees small enough to fit into limited space are not available for plums. Fan-training against a sunny fence or wall or pruning to form ‘pyramids’ are good alternatives.

Like most tree fruits, plums are produced by ‘grafting’, or its summer equivalent ‘budding’, the cultivar scion onto a rootstock that controls the tree size and earliness to fruit or precocity.