European plums (Prunus domestica) typically do not require a compatible tree for pollination while most Japanese (Prunus salicina) plums do. Cross-pollinating trees have to yield flowers and bear pollen at the same time, so some combinations of cultivars work while others do not.
Main Plum Varieties
Japanese plums, sometimes called Asian plums, are juicier than European plums but not quite as sweet. The term used to indicate that they need another tree for pollen is that they are "self-unfruitful."
A European plum tree planted alone will bear fruit, meaning it is "self-fruitful," but if it receives pollen from another European cultivar, it will yield more plums.
To help the consumer select compatible cultivars for cross-pollination, plum trees are often grouped into early, mid-season and late season varieties.
European plums typically grow better in colder climates. Here are some examples of European plum varieties and some cultivars suitable for cross pollination to increase plum yields.
The greenish-yellow Valor plum (Prunus domestica ‘Valor’), U.S. Department of Agriculture plant hardiness zones 5 through 9 may be pollinated by:
(Prunus domestica ‘Italian’), self-fertile, USDA zones 5 through 8.
(Prunus domestica 'Stanley'), self fertile, USDA zones 4 through 9.
The large, round Seneca plum (Prunus domestica 'Seneca'), USDA zones 5 through 8, may be pollinated by:
(Prunus domestica 'Damson'), USDA zones 5 through 7.
Gage (Prunus domestica 'Green Gage'), USDA zones 4 through 7.
Almost all Japanese plums need a compatible pollinating tree. As with European plums, a self-fertile Japanese plum tree will yield more plums if it receives pollen from a compatible cultivar. Here are a couple of examples of self-fruitful Japanese plum trees:
- Simka (Prunus salicina ‘Simka’), USDA zones 5
- Alderman (Prunus salicina 'Alderman'), USDA zones 5 through 9.
Here are some examples of Japanese plums cultivars and some varieties useful for cross pollination. All of these cultivars will grow in USDA zones 5 through 9.
The red-skinned Satsuma (Prunus salicina 'Satsuma') can be pollinated by:
- Santa Rosa (Prunus salicina 'Santa Rosa')
- Shiro (Prunus salicina 'Shiro')
The yellow-skinned Shiro (Prunus salicina 'Shiro') can be pollinated by:
(Prunus salicina 'Burbank')
(Prunus salicina 'Vanier')
All four of these cultivars are hardy in USDA zones 5 through 9.
Although Japanese plums will survive winters, they do better in warmer climates. Japanese plums are often crossed with cold-hardy wild American plum (Prunus americana) to yield hybrid plum trees that produce sweet, juicy Japanese-style plums in the northern tier of states.
Hybrid plums need a pollinating tree. They can be pollinated by another hybrid plum or by the American wild plum.
Methey (Prunus salicina ‘Methey’), USDA zones 5 through 9, is an example of a self-fruitful Japanese-American plum hybrid.
European plums are also crossed with American plums to form hybrid varieties, but less often. The plums yielded by hybrid trees are smaller than pure-species trees. European-American hybrids need a pollinating tree.
American plums, wild plums that typically grow in a bush-like form and yield small plums, need another American plum tree for pollination. While they will pollinate a hybrid plum tree, they will not pollinate a European or Japanese plum variety.
American plums will grow in USDA zones 3b through 8.