Does a Satsuma Plum Need Cross Pollination?

Satsuma Plum

• Plums (Prunus spp.) are grouped into two primary types -- European (Prunus domestica) and Japanese (Prunis salicina). Japanese plums are preferred choices for warmer climates, such as the southern and western states, because the trees require fewer chilling hours to set fruit. Satsuma is a Japanese variety that grows in U.S. Department of Agriculture plant hardiness zones 4 through 9. The trees bear small, round fruits that have red skins and red flesh. Typically, Satsuma bears prolifically if it is pollinated adequately.

Pollination

• Satsuma plum trees are considered self-unfruitful, because they cannot pollinate their own flowers sufficiently. Although some trees may self-pollinate, their resulting fruit yields are spotty at best. Satsuma trees must “borrow” pollen from another variety that is able to fertilize its flowers. This process is called cross-pollination, because the pollen is transferred by crossing from one tree to another. The ability of another tree to pollinate Satsuma requires that both trees are flowering at the same time. Because different plum varieties blossom at various times, bloom times must be compatible for successful cross-pollination.

Compatible Pollinizers

• A pollinizer is a tree that lends pollen to another tree for cross-pollination. Shiro and Burbank are Japanese plum varieties that are recommended as compatible pollinizers for Satsuma. Formerly, Santa Rosa also was recommended as a compatible pollinizer, but because of its vulnerability to bacterial diseases, notably plum leaf scald, it no longer is a sound choice. Shiro trees bear yellow plums and Burbank trees bear reddish-purplish fruits that have red flesh. Regardless of your pollinizer choice, the resulting Satsuma fruits characteristically are red.

Considerations

• Proximity is a critical factor for successful cross-pollination. Trees that are planted further than 100 feet from each other may have reduced yields. Although honeybees are the primary pollinators of Satsuma, the wind also may pollinate the flowers. If trees are too far apart, wind pollination reduces the overall fruit set because pollen grains cannot be transported over long distances. Bee pollination may be hindered in cool weather, because bees are most active at temperatures above 65 degrees Fahrenheit. Bees are particularly sensitive to many pesticides, which can kill them, so the judicious use of chemicals, particularly when plum flowers are blooming, helps keep honeybee populations intact.