A boysenberry is a type of glossy, large, juicy berry that is related to the North American blackberry. In addition to being eaten fresh during their brief growing season, they also can be incorporated into jams, preserves and syrups. Their flavor is somewhat reminiscent of raspberries with a more tart undertone, especially when the berries are not fully ripened. They are available from grocery stores and farmers' markets, but they are not very stable off the vine, so it is important to eat them within two or three days of purchase.
The inventor of the boysenberry is believed to Rudolph Boysen, who experimented with various berry crosses in Napa, California, during the 1920s. In 1923, his cross of a blackberry, loganberry, and raspberry successfully grew and bore fruit. The combination was acquired by Walter Knott, a Southern California berry farmer, who started selling the fruit commercially in 1935. Boysenberries and their preserves helped make Knott's business quite famous.
The distinctly tart flavor of fresh boysenberries makes them very popular in areas where they can be obtained. When selecting ones to take home, shoppers should look for evenly sized and evenly colored specimens that have no areas of mushiness. The berries should be kept under refrigeration in a watertight container far from apples and bananas, which emit ethylene gas.
If the berries are not going to be used within three days of purchase, a person should consider using them to make jam. They can be scattered fresh on pancakes and waffles, used as a pie filling, or added as a decorative accent to cheesecakes and tarts. The berries also can be eaten plain or as part of a fruit salad.
To grow boysenberries at home, gardeners should find a patch of land that receives full sun and minimal wind. The soil should be tilled thoroughly, working in plenty of compost and mulch. Vines should be planted about 3 feet (0.9 m) apart in the late spring colder climates or the late fall in warmer climates.
Trellises should be installed for the trailing vines to grow on so that they will be pulled up off the ground, making the berries easier to harvest and less likely to rot. Typically, boysenberry vines will bear fruit in the spring, after which they should be cut down close to the ground to encourage fresh shoots, which will bear berries again the next year. The plants should be watered thoroughly after they are cut back, and the vines should be retrained as they grow.