Pruning blackberries creates a neat appearance, encourages the plant to produce more fruit, and keeps the blackberry thicket tangle-free. Pruning thornless blackberries is easier than pruning traditional blackberries with thorns, but with a pair of good gloves and sharp shears you can prune both with equal ease.
Facts About Pruning Blackberries
Pruning blackberries yearly encourages more fruit production and makes cultivation easier.
When to Prune
Blackberries produce two types of canes or stems: primocanes and floricanes. Some produce fruit on both types of canes, while other types produce fruit only on the floricane.With these blackberries, primocanes create new stems, while floricanes produces flowers and after pollination, blackberries. It's important to know the difference because each type of cane is pruned at a different time of year and at a different point in the plant's growth cycle. How to tell the difference? Just look carefully at the canes. Primocanes don't produce flowers or fruit and may have a flush of new growth at the tip. Floricanes produce blossoms in the spring and berries in early to mid summer. Prune primocanes or stems without fruit and berries in June and July, but wait to prune the floricanes until after berries are picked.
Some blackberries, such as Prime and Prime Jim types, bear fruit on both the primocane and floricane. For these types, wait until berries are picked before pruning. Many gardeners wait until the first frost, then prune these blackberry bushes almost down to the ground to keep them contained and controlled.
How Much to Prune
When pruning blackberries, cut the primocanes down to about 48 inches, measuring from the ground up to the tip of the cane. Shoots develop off the main stem. These are called lateral shoots. They jut out to the sides. You can prune these back to around 18 inches towards the end of the summer.
Floricanes are pruned differently. After all the fruit is harvested, wait until the end of the summer or into the early fall. Prune branches that bore fruit down to the ground, or at least as far down as you can reach comfortably.
For types that bloom and produce fruit on both primocanes and floricanes, wait until the first frost of fall, then simply cut back the entire bush. You can cut it pretty low to the ground.
Tools and Tips
You don't need special tools for pruning blackberries. If you're working with plants with big thorns, wear jeans, a long sleeved shirt, and heavy canvas, leather or suede gardening gloves. A sharp pair of loppers or garden pruners are sufficient for most pruning jobs. Be sure to clean pruners after use. Dry the blades to prevent rust and store tools properly in a shed, garage or basement so as not to expose them to the elements.
Reasons to Prune Blackberries
Pruning blackberries takes time and effort. The rewards are worth the effort, however. Leaving plants to grow wild does not produce more fruit. In fact, taller plants often have tangled canes, which prevents or discourages fruiting. Pruning encourages blackberry plants to produce abundant fruit. It increases air circulation among the canes, which discourages fungal diseases from attacking the plants.
For more information on pruning blackberries, including pictures showing what they should look like after pruning, visit the University of Missouri Coopeartive Extension. Your own local cooperative extension may also offer fact sheets or pamphlets to help you get started pruning blackberries.
