Family: Rosaceae

Cultivars of the European group (the species mentioned below) are commonly grown plums. The Japanese plums (Prunus salicina cultivars) grow best in the warmer climate of the west. In severe climates a group of hybrids produced from American wild plums, Japanese plums and other species is grown. Believed to have originated from the temperate zones of Eurasia, the plum has been cultivated for longer than any other fruit, apart from the apple. It is also said that Alexander the Great introduced the plum into Greece from Syria or Persia, where the damson plum has been growing for a very long time. The plum is grown not only for its fruit but also as an ornamental, because of its variously coloured flowers and foliage.

Species

Prunus domestica, common or European plum, is a mostly deciduous and low-growing tree, with a broad spread. It is the earliest fruit tree to blossom, flowering before the foliage appears. Oval or globe-shaped, the edible fruit is either clingstone or freestone, with juicy flesh which is generally yellow in colour. There are many cultivars and a good fruit nursery will be able to offer a wide selection suitable for your area. For instance, the greengage types are truly delicious and well worth growing, having round, green fruits which are very sweet and therefore good for dessert. Also consider the transparent gages where the actual stone can be seen through the flesh. These are also good for dessert. Then there are the prune type of plums, which have dark purple skins and very sweet flesh. These are normally grown for drying.

Damsons are also grown in the UK, being selections from P. insititia. The small fruits are very tart and are mainly used for jams and jellies. The trees are small and compact, and there are several, self-fertile cultivars available, ideal where space is limited. The Japanese plums are from P. salicina, and are also known as salicine plums. 'these have round fruits, usually quite large, with skin colour purple, red or yellow. They are most widely grown in California. There is a number of self-fertile cultivars which should be considered where space is at a premium. When buying the hardy hybrids bear in mind that there can be problems with pollination, so do check out their pollination requirements at a fruit nursery.

Cultivation

European plums like heavy clay soils, while Japanese plums prefer a lighter soil. Good drainage is essential for both and adequate water is necessary once the fruit has begun to develop. Propagate by budding onto different rootstocks. Though the flowers are bisexual, it is best to plant another recommended variety for pollination. Few plums set good crops without cross-pollination. It is essential to select the right pollinator for optimum cropping, but a fruit nursery will be able to advise on this. Pruning in the early years involves shaping the tree to develop strong leaders and an open centre. As the plum is borne on the same short stems or spurs, year after year, pruning is needed to bring on new fruiting wood. Reduce the number of stems to prevent overcropping and improve fruit quality. Tip prune the branches to keep the tree from becoming too tall, cut out dead wood, and keep the centre of the tree open. Pruning is done in early summer to avoid infection from the disease known as silver leaf. All large wounds should be painted with proprietary pruning paint. Contact your local nursery for more information on the varieties grown in your area. The plum can be attacked by brown rot, birds, borers, fruit fly, rust, shot hole and bacterial canker. Shot hole is very common in humid areas.

Climate

European plums are best in zones 6 to 8. Japanese plums are ideal for zone 9. Hybrids of the American and Japanese plums are suited to the north central US.