BRAMBLES IN THE FIRST YEAR grow in a pattern of new canes (called primocanes), which then produce fruit in the second year (floricanes), before dying off. Another way to describe brambles is that the crown (the base of the plant from which canes sprout) is perennial and long-lived, whereas the stems are biennial so only live for two years.
For the purpose of pruning advice, blackberries, boysenberries, tayberries,loganberries and hybrid berries are treated similarly.
Raspberries are also a bramble, but pruning is slightly different between summer- and autumn-fruiting types. As a general rule, each plant has a combination of new canes and fruiting canes. To keep plants tidy and productive, the floricanes that have produced a crop and died off should be pruned off in the winter following harvest. It’s best to wait until the plants are dormant before pruning, as this gives time for carbohydrates from the floricanes to return to the crown for energy storage. During the summer, primocanes will have formed, so don’t remove these when pruning out the floricanes, because they will produce the fruit in the following season.
CULTIVATED BLACKBERRY varieties have upright growing canes – unlike their cousins in the wild, which have a trailing habit. Allow the new canes (or primocanes) to reach 1m, then cut to encourage branching for more fruit on the tips of each lateral. You can use manual or electric hedge trimmers to make it quick and easy.
TAYBERRIES AND LOGANBERRIES are hybrids of blackberries crossed with raspberries, but should be pruned like a blackberry. New canes can grow rampantly – nearly 2m in a single year – so taming them by training them along wires is necessary.
BOYSENBERRIES are a trailing type of blackberry, so naturally spread horizontally along the ground. When cultivated in orchards and home gardens, these need to be lifted onto a wire frame to support the canes, which will make picking easier.
Pruning of boysenberries is an annual winter event. The canes attached to the wires will have died back, so these need to be removed. During the previous summer, new growth will have sprouted, and will probably be lying untidily on the ground. These long canes should be carefully gathered up with gloves to avoid the spines, lifted and wrapped around the wires. Another way to deal with the natural growth of boysenberry canes along the ground is to have a split wire system. One side (for example, the left) holds the fruiting canes, while the other side (the right) has the new canes growing up (instead of just being left along the ground).
In winter, the fruited canes on the left will have died off, so should be removed. In the following summer, the right side canes will be fruiting, and the new canes will be trained onto the left side wires. Each year, you should alternate the training from side to side.
SUMMER-FRUITING RASPBERRIES STEP 1: In autumn or winter, remove all the older canes that produced fruit in the previous season, cutting close to the crown at the base of the plant. Take care not to damage or remove any of the newly grown canes – these will produce the first crop of berries the following summer. Your goal after pruning is to have 10-12 fruiting canes per plant (or per metre, if growing in a row). Some varieties with less erect canes will require wires for support.
Prune the new canes back if their height in winter reaches way above the support wires. Also consider the height in relation to the weight of the fruit – you don’t want weighed-down or broken canes. Don’t prune the tips of the new canes by more than 25 per cent though as this will reduce your crop. STEP 2: Next, remove any wandering canes sprouting outside of the designated raspberry bed. Raspberries have a large root system and will send up lots of suckers, sometimes a metre or more away from the parent plant, so keep an eye out for escapees and cut them off at ground level where they emerge. Don’t let the raspberry bed get too wide, as it will make pruning and harvesting difficult, as well as increasing the risk of fungal diseases getting a toehold. In humid areas, consider pruning spent raspberry canes in autumn to encourage air movement and prevent disease. The time you prune is not the most critical, so long as you do it before spring, but it’s easier to see what you are doing when the plants have lost their leaves.
AUTUMN-FRUITING RASPBERRIES fruit on canes produced during the current year, so pruning them really couldn’t be easier: all canes should be cut off at ground level in winter. The new canes that grow next season will fruit at the end of the summer and into the autumn, so select the strongest 10-12 fruiting canes and tie them in to the supporting wire.
You can also buy dual-fruiting varieties; these fruit in summer and again in autumn. After they have finished fruiting in autumn, cut by half the stems that have just carried fruit back. In spring those stems should put on fresh growth at the tip and it’s this new growth that will bear fruit in the summer. Then, once the fruit has been picked, cut those two-year-old canes back to ground level.