Like raspberries, youngberries, loganberries and blackberries, to which they are related, boysenberries are known as bramble fruit. Boysenberries are actually a variety of blackberry. This perennial produces fruit on canes that live biennially; the plant sends up canes, the canes bear fruit in two years, then the cane dies. Because they can spread as brambles, boysenberries can be grown on trellises. Growing boysenberries this way uses less space and makes it easier to pick the fruit. Boysenberry should be planted in early spring.
Dig up and dispose of any wild berry plants in the vicinity because they might transmit disease to your plants.
Choose your planting spot. It should be in full sun and preferably- slightly sloped, which will help with drainage.
Prepare the site by deeply incorporating compost or other organic matter. Boysenberries grow best in a well-draining soil like sandy loam enriched with organic matter.
Find out how deep the boysenberry was planted in the nursery. Plant the boysenberries about three feet apart at the same depth they grew at the nursery.
Wet the soil so it's moist, not soggy.
Cut the plants to about 6 inches high.
Mulch the plants with about four inches of mulch to retain moisture and control weeds.
Water the plants regularly so the roots stay moist, every other day for the first week, then one to two times per week afterward.
Pick the berries when they are completely ripe, about twice per week during the fruiting season.
Cut canes to the ground once their fruiting is finished.
Fertilize every spring.