Naturally fat free. In 1932 Walter Knott was the first person to cultivate the boysenberry plant, naming it after Rudolph Boysen, who produced the original hybrid. The new berry combined the best quality of the blackberry, loganberry, and raspberry. Today you can trace every boysenberry in the world back to Knott's Berry Farm, where Walter nurtured the first boysenberry vines and wife Cordelia cooked her first batch of boysenberry preserves.