Visions of beach plums — particularly of beach plum orchards on South Jersey farms — are running rampant in Cape May County, NJ. The beach plum, prunus maritima, is the subject of a $40,000 New Jersey Department of Agriculture 2015 Specialty Crop Block Grant. With this funding, the Cape May County Beach Plum Association has big plans for the wild native, found not only in New Jersey, but in coastal areas from Maine to North Carolina.
“The plant can survive in different environments between Maine and North Carolina in the wild, but that doesn’t grow quality fruit,” Jenny S. Carleo an agricultural and resource management agent at Rutgers New Jersey Agricultural Experiment Station, Cooperative Extension of Cape May County, said. “The grant will enable us to develop better tasting varieties, higher fruit quality and more consistent flowering time.”
Those three issues have been hindering commercial beach plum production for years. The plants themselves vary in form as well as flowering time, which would affect any spray programs. Progeny from seed are also highly variable, and the fruits vary widely in taste. About 50 years ago, there was a surge of activity in beach plum cultivation, which continued locally until about 1980, but researchers and growers could not overcome these obstacles. Today, however, advances in technology promise that the beach plum can, in fact, be domesticated.
“The [beach plum] acreage is expanding from year to year,” Carleo said. The resurgence began around 2006. There has been a lot of effort going into research on best production methods, breeding, marketing and value-added production over the past few years. The USDA grant will allow an increase in Extension education programs and outreach, develop a beach plum promotion program and increase the number of high-quality plants available to interested growers.
Dune to Orchard
Beach plums grow along the secondary sand dunes in the wild, where they help stabilize the sand. They are used in dune restoration projects, so nursery growers have this market, too, as well as the emerging market for fruit production. They grow primarily in shrub form, and sometimes in tree form, ranging in size from small to large. In the wild, the plants often grow leaning to one side, which is believed to be an adaptation to constant winds off of the sea.
This leaning, multi-branched shrub form isn’t ideal for commercial production. At Rutgers Fruit and Ornamental Research Extension Center in Cream Ridge, Professor Joseph Goffreda, director and fruit breeder, maintains a beach plum orchard. Established about 10 years ago, the beach plums at Cream Ridge are inland from the sea, and growing on a heavier soil, demonstrating their adaptability to non-coastal environments. Their pH requirements are in the 6.5-7.0 range. Although their water requirements are debated among researchers, Rutgers research has found that irrigation, particularly when establishing the orchard, is best for optimal fruit production, but this could also be dependent upon soil type.
Goffreda has introduced a sterile variety of beach plum for landscape plantings, but for farmers, Goffreda also developed a hybrid, BP1-1. The taste tends towards the sweet side, giving hope that some beach plums may be suitable for the fresh-eating market. Most beach plums are used in making value-added products, including wines, jams, vinegars and syrups.
Observational experiments on a 1,000-tree commercial orchard, conducted by Rutgers Cooperative Extension and the CMCBPA, led to the recommendation that trellising the plums, after training them to a central leader, is the best method for commercial production, Carleo said. Experiments with an open-vase pruning system were not adaptable to trellising, which prevents the trees from leaning, as they naturally do in windy conditions.
The trellising system recommended is based on pruning a one-year-old plant to one stem, 18 inches tall, which will encourage healthy branching. At year two, between three and five scaffold limbs should be selected, located around the tree. As the tree grows, another selection of scaffold branches should be made about three feet above the first. The trellis will consist of three high-tensile wires, with the topmost at seven feet. Fruit is ready to be harvested the third year.
While the trellis prevents the leaning seen naturally in the beach plum, some growers feel that trellising is too expensive, or that the natural habit of the plant should be encouraged, rather than subdued. Some prefer to leave the plant in a shrub-like form, more akin to a blueberry bush. Spacing in the orchard has also been widely debated by growers. Some see the benefit in wider spacing, while others prefer tight orchard row spacing.
For now, it is recommended that growers use the same spray program as for plums. Brown rot of some type is a known disease issue, as is plum pocket disease, which swells and then kills the fruit. Thinning requirements aren’t known, and the plants have a tendency to bear in alternate years. Frost tolerance isn’t well-documented either, and while the plants are sea-spray tolerant, whether they can be grown in soils with higher salinity levels from saltwater encroachment isn’t known.
Harvest and Market
Harvesting is almost entirely done by hand. The fruits do not ripen simultaneously, so each bush has to be harvested three or four times if only ripe fruit is desired. Traditionally, some green fruit is used in the making of jams, to achieve the desired flavor profile. For beach plum wine, however, only ripe fruit is used.
Dr. Amy Howell, associate research scientist, Philip E. Marucci Center for Blueberry and Cranberry Research and Extension, has examined the anti-oxidant properties of the beach plum fruit. The beach plum’s antioxidant profile is similar to that of blueberries and cranberries, and it is also believed to have bacterial anti-adhesion properties, and possibly could play a role in preventing urinary tract infections.
Beach plums can be readily frozen. The pit, however, can be an obstacle for some food processors.
“It’s really a cottage industry at this point,” Carleo said of beach plum growing and processing. But she predicts that within the next 10 years, commercial beach plum crop production will have become a reality. “Blueberries started like this 100 years ago.”