Plants grow horizontally, compared to the erect habit of most blackberries. To grow, most plants are tied to supports or wires to limit their trailing habit.
Fruits are sweeter, ripen sooner and are in looser clusters.
Boysenberries are not winter hardy and need protection from cold temperatures. Plants should be untied from supports and lain horizontally after the ground starts freezing. Cover canes with straw or loose hay at least a foot or more. Prune boysenberries in a similar fashion to blackberries. Boysenberries, like most trailing blackberries, are difficult to grow in Illinois.