A boysenberry /ˈbɔɪzənbɛri/ is a cross between a European Raspberry (Rubus idaeus), a Common Blackberry (Rubus fruticosus), an American Dewberry (Rubus aboriginum) and a Loganberry (Rubus × loganobaccus).
It is a large 8.0-gram (0.28 oz) aggregate fruit, with large seeds and a deep maroon color, which changes to the typical boysenberry color when the fruit is cooked and made into jam and pie.
The exact origins of the boysenberry are unclear but the most definite records trace the plant as its known today back to grower Rudolph Boysen, who may have gotten the dewberry/loganberry parent from the farm of a man by the name of John Lubben (who called it a "lubbenberry"), who in turn may have gotten it from Luther Burbank.
In the late 1920s, George M. Darrow of the USDA began tracking down reports of a large, reddish-purple berry that had been grown on Boysen's Northern California farm. Darrow enlisted the help of Walter Knott, a Southern California farmer who was known as a berry expert. Knott had never heard of the new berry, but he agreed to help Darrow in his search.
Darrow and Knott learned that Boysen had abandoned his growing experiments several years earlier and sold his farm. Undaunted by this news, Darrow and Knott headed out to Boysens old farm, on which they found several frail vines surviving in a field choked with weeds. They transplanted the vines to Knotts farm in Buena Park, California, where he nurtured them back to fruit-bearing health. Walter Knott was the first to commercially cultivate the berry in Southern California. He began selling the berries at his farm stand in 1932 and soon noticed that people kept returning to buy the large, tasty berries. When asked what they were called, Knott said, "Boysenberries," after their originator. His familys small restaurant and pie business eventually grew into Knotts Berry Farm. As the berry's popularity grew, Mrs. Knott began making preserves, which ultimately made Knotts Berry Farm famous.
By 1940, 599 acres (242 ha) of land in California were dedicated to boysenberries; the number would trail off during World War II but peak again in the 1950s at about 2,400 acres, to the point where boysenberry crops exceeded those of the (previously) more common raspberry and blackberry. By the 1960s, the boysenberry began to fall out of favor due to a combination of being difficult to care for, susceptible to fungal diseases in coastal growing areas, too soft and delicate to easily ship without damage, and having a short season of availability compared with newer cultivars. As of the early 2000s, fresh boysenberries are generally only grown for market by smaller farmers and sold from local farm stands and markets. Most commercially grown boysenberries, primarily from Oregon, are processed into other products such as jam, pie, juice, syrup, and ice cream. Since 2007, a hybrid variety called the "newberry" or "ruby boysen", developed to overcome some of the shortcomings that led to the boysenberry's decline in popularity, has been marketed through retailers in California and nearby states.
New Zealand is today the worlds largest producer and exporter of boysenberries.