By National Gardening Association Editors, June 23, 2008
- Some plums are self-fertile but all plums will yield better if planted with a second variety for cross-pollination. Japanese plums need to cross-pollinate with other Japanese or American hybrid plums.
- Order bare-root, rather than potted trees, if possible.
- A well-established tree will yield up to 2 bushels of plums.
- Select a site that offers loamy, well-drained soil in full sun.
- Avoid frost pockets.
- Set the tree in the prepared hole keeping the graft union an inch above the soil line.
Space standard-size varieties 20 to 25 feet apart, dwarfs 15 to 20 feet apart.
- Water young trees heavily every week through the first season.
Train Japanese trees to an open center shape; train European trees to a conical shape with a central leader.
- Japanese plum trees benefit from a moderate fruit thinning; do not thin European plums unless the crop is especially heavy.
- Plums are relatively pest-free, but may be visited by the plum curculio, black knot disease, and brown rot. See our article Fruit Pests and Diseases for controls of these problems.
- Harvest European plums when they are tree-ripe. They will be a little soft and should come off easily with a slight twist. Late maturing varieties should be near ripe with firm flesh for storing for a few weeks.
- Pick Japanese plums slightly early and allow them to ripen in a cool place.