Boysenberries are something a little different if you want a berry type fruit for the garden. They are very similar to a blackberry where they produce large, dark purple fruits. They are also extremely juicy and sweet combining crosses from a number of parent species including dewberry which is an American trailing blackberry, loganberry (a cross of a raspberry with blackberry) and a true raspberry. With all these qualities, boysenberry is ideal for preserves, jams, sauces, fruit pies or like raspberries, eaten straight off the bush. They are not grown commercially like they used to be but they still offer the home grower a great alternative to more standard types of fruit.
Boysenberries need full sun and are hardy in the UK except in the far north of the country. Varieties come with or without thorns but always choose a certified disease-free stock.
Plant in a moisture retentive soil that is free-draining, enriched with lots of rotted organic matter. Cover the root ball with this matter to around 8cm of soil. Mulching on this scale reduces weed hoeing which reduces the potential damage to emerging shoots. The next step is to cut the canes down to a healthy bud to encourage strong new growth in spring.
Boysenberries flower on the previous season’s canes. Don’t expect fruit until the second year. they need lots of space so allow 3cm between them if you are planting more than one.
Aftercare and Continued Care
Like all hybrid berries, these canes need a support system. Construct one before you start planting. Tie the stems to horizontal wires, either against a fence or a wall or by using freestanding posts, with the first wire 23cm from the ground and subsequent wires at 45cm intervals.
Boysenberries flower and fruit on canes in their second year, so cut down the current year’s canes to ground level after fruiting in mid-Autumn. Select new canes that are around pencil thickness, and, using soft string, tie these onto the wire in a bundle to over winter, removing thin or particularly short canes. The following spring, untie the bundle and tie the canes along the wires before they start to put on new growth.
Ensure canes get enough water, especially in early summer before the berries ripen, and apply a general purpose fertiliser annually in the spring. Boysenberries are quite vigorous, be prepared to thin some fruiting canes in the warmer months.
Pests & Diseases
Birds will always go for the juicy ripe berries without fail. Cover with a net before they ripen. Blackberry cane spot which reveals itself as grey spotting on the canes can cause the canes to enlarge and split. Affected areas need to be pruned out to the ground and the affected material burnt or binned. Don’t compost !
Harvesting And Storage
Collect the ripe berries with the small calyx attached. Either eat immediately, or store in the fridge for a few days. Freezing is possible if you want fruit for baking and juicing.