Beach plums (Prunus maritima) are best known for the fruits they produce in August/September, which are popular in jams and jellies, but they are most easily spotted this time of year, even from a distance, due to their showy displays of bright white flowers. The flowers bloom in May before the leaves emerge. Although these short, densely-branched beach plum shrubs appear rather scraggly-looking prior to leafing out, they will soon fill in with alternate, simple, approximately 2 inch long leaves with serrated margins. Belonging to the same genus as cherries (Prunus), beach plums also have reddish-brown to purplish bark with distinctive lenticels (horizontal bands) common to that group of plants.

Beach plum shrubs appear rather scraggly-looking prior to leafing out. 

 

Like cherries, beach plums have reddish-brown to purplish bark with distinctive lenticels.

Beach plums are well adapted for maritime life and make their home in the coastal dunes and other seaside areas from Virginia to Nova Scotia. Their ability to survive in a difficult coastal environment, coupled with their deep penetrating root systems, make this plant useful in restoration projects aimed at stabilizing coastal dunes. In fact, as additional wind-blown sand is trapped by the plant and accumulates at its base, lower branches that get buried will develop adventitious roots to further stabilize the dune.  

Most beach plums cannot self-pollinate and require cross pollination with another beach plum plant for a good fruit set. Bees are the most common pollinator. However, a given beach plum shrub may produce copious fruit one year, and not the next. This variable fruit production could be due to the weather at the time of blooming. A late frost can destroy the blossoms and cold weather during the time of blooming can inhibit pollinator activity, both of which would greatly affect the quantity of fruit production that year. Another theory is that beach plums go through what is called “alternate bearing”, which happens with other related cherry and apple tree species. Because flower buds for next spring are developing while this year’s fruits are ripening, a heavy fruit set one year can lead to a carbohydrate shortage resulting in fewer blossoms the following year. However, while irregular fruit bearing may disappoint those hoping to take advantage of the late-summer fruit harvest (both humans and wildlife), it does not seem to harm the plant. 

Beach plums are commonly pollinated by bees.