American Plum as a Cross-Pollinator

American Plum Pollen

• American plums are shrubs small trees that grow from 3 to 34 feet grow, usually growing in thorny thickets. They blossom in groups of two to three white flowers that look like small roses before the leaves appear in April or May. They yield 3/4 to 1 1/2 inch long yellow or red plums that grow in clusters. Each tree provides its own pollen; bees and other pollinating insects move the pollen from flower to flower,

Pollination Basics

• Some plum varieties are self-fruitful, producing fruit using their own pollen. Other varieties are self-unfruitful, meaning they need pollen from another tree to yield plums. The pollen from self-unfruitful varieties may be used to pollinate other plum varieties, but typically not as well as that from self-fruitful varieties. While all plum varieties yield pollen, some cultivars do not produce enough viable pollen to successfully pollinate another tree.

European and Asian Plum Pollination

• If a plum is fat, red and juicy, it is likely a Japanese plum. European plums are smaller and either blue or purple, although they may be yellow or green. European and Asian plum trees will not cross-pollinate. Most European plums are self-fruitful, but if they are not grown near a pollinating cultivar, they bear poorly. To bear a full crop of fruit, they need a pollinating tree. All Japanese plum trees except "Santa Rosa" (Prunus salicina "Santa Rosa") need pollen from another tree to produce plums, although “Santa Rosa” does need a pollinating tree to produce a full yield of plums. It will grow in USDA zones 5 through 9.

Climate and Pollination

• Plum cultivars may yield early, mid- or late season blossoms. If two trees do not bloom at the same time, they cannot pollinate one another. In selecting plum cultivars that will cross-pollinate, select those that bloom at the same time in your climate. Nurseries typically sell cultivars appropriate for their local climates and the tag will tell you whether a cultivar is an early, mid- or late season bloomer. Although their growing zones vary by species, European plums are typically more cold hardy than Asian plums and will grow in USDA plant hardiness zones 5 through 10, depending on the variety. Asian plums generally tolerate warmer weather, and most cultivars will grow in USDA zones 7 through 10, also depending on variety.