Boysenberry  moderately vigorous plant tailing variety grown in California but also to some extent in Oregon and Texas.  Boysenberry vines often make a growth of 10 feet or more and production of 5 tons of berries per acre is average and as much as 10 tons per acre have been recorded.  The berries are large and long, 1 1/4 inches long by 1 inch thick, dark reddish black when fully ripe, and has slightly more acid than the Youngberry.  The Boysenberry's origin is unknown but it is thought that it may have been commercially introduced by Rudolph Boysen of Anaheim California in 1926.