Plant Japanese plum trees in full sun, in moist, but well drained soil. Avoid low-lying frost pockets or wet areas with poor drainage. As they are less hardy than European varieties, shelter them from cold and wind. Japanese plums are not self-fertile and require additional Japanese plums in the area for cross-pollination. European and Japanese plums will not cross-pollinate each other. Fruit can be picked once it has coloured, become soft and is easy to pick off the tree. Prune in early spring (March) and then thin them out again in summer. Do not prune in the winter. Spray a lime sulphur-dormant oil spray in winter to kill over-wintering insects. A copper spray in summer can also be beneficial. Apply a fruit tree and berry fertilizer in early spring as growth begins.