How to Prune Raspberry and Blackberry Plants

Raspberry plant

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Two of the most popular shrubby fruit plants in North America are raspberries and its close relative, the blackberry. Both species are from the Rubus genus, and both are known as bramble fruits, which grow in dense shrubby masses that can be almost impenetrable once they are fully mature. Yet despite the fact that it is difficult (and sometimes painful), pruning these plants is essential for a number of reasons. Left unpruned, these bushes will spread by suckers and grow into massive spreading plants with lower fruit production and susceptibility to disease. If you want to continue to enjoy their delicious fruit and keep them from overtaking your garden, learn the proper ways to prune raspberry and blackberry bushes, and the proper time to do it.

Working With Raspberries and Blackberries

Both raspberries and blackberries have serious thorns, so wear thick gloves and long sleeves when pruning. Skin punctures can easily become infected. Always use clean, sharp tools when pruning these bushes. Canes that are crushed rather than cleanly severed can provide an avenue for insects and disease-causing pathogens.

There are two bearing categories for raspberry plants:

  • Summer-bearing (floricane) raspberries will provide one large harvest, usually in late summer or early fall. Summer-bearing raspberries bear fruit on 2-year-old canes, the ones that sprouted last season. Summer-bearing raspberries can be further categorized as early season, mid-season and late season. The harvest period lasts about 4 to 5 weeks.
  • Everbearing (primocane) raspberries aren't really everbearing, but they do generally have two harvests per season—one in mid-late summer and one in the fall. The fall crop will probably be a bit lighter and is produced on 1-year-old canes that developed during the current season. Many fall-bearing raspberries bear so late in the fall that they are not practical for gardeners in short-season climates.

The goal when pruning these fruit bushes is to ensure that light and air can get inside the plants. To facilitate pruning, keep the plants controlled in a row. Keep the base of the bushes within a 12- to 18-inch footprint by pruning out any suckers that poke up outside that boundary. The tops of the bushes will arch nicely, providing plenty of fruit.

Pruning blackberries is quite similar to pruning raspberries, but it is even less complicated. Blackberries don't grow as enthusiastically as raspberries, but they, too, will yield better with regular pruning. And as with raspberries, they can be prone to diseases that spread rapidly if the plants aren't maintained.

When to Prune Raspberries and Blackberries

Raspberries are generally pruned at two times of the year: in late winter or early spring before bud break, and during the summer growing season for basic maintenance.

Blackberries are also pruned at two times of the year: in the early spring when they are "tip-pruned," and in the late summer for general clean-up of the bushes.

What You'll Need

Equipment/Tools

Project Metrics

  • Working Time: Depends on size of planting; about 1 hour to prune a 10-foot-long row
  • Material Cost: None

Instructions

Pruning Summer-Bearing Raspberries

  1. In late winter or early spring, prune out all canes that bore fruit last year; they won't fruit again. These will have grayish, peeling bark. Cut them off near ground level, using loppers or a pair of bypass pruners.
  2. Remove any canes that have grown outside the 12- to 18-inch designated row footprint. Raspberries are much easier to tend and harvest if they are kept confined in well-defined rows. Don't worry about pruning too vigorously; raspberries are very hardy and you really can't prune too aggressively.
  3. Remove any spindly or short canes.
  4. Thin out the canes so that there are about four or five of the healthiest, tallest, and fattest canes left per foot along the entire length of the row.
  5. Tie the canes to your fencing or stakes for support.
  6. During the summer, prune out any dead, broken, or diseased canes that you spot, as well as any canes that sprout up outside the designated row area.

Pruning Everbearing Raspberries

If you want everbearing raspberries to produce two crops each year, prune them as you would summer-bearing. But if you want to force a single larger crop in the fall, follow this procedure:

  1. To force your everbearing raspberries to produce only one crop in the fall, prune back the entire raspberry bush to ground level in early spring.
  2. As the canes grow back in the summer, remove outside suckers and thin the canes to about 6 inches apart. Keep the sturdiest canes. This technique will give you a larger fall harvest and works well if you also have summer-bearing raspberry bushes and you want to stagger the harvests.
  3. During the summer, prune out any dead, broken, or diseased canes that you spot, as well as any canes that sprout up outside the designated row area.

Pruning Blackberries

  1. In the fall, prune out all canes that bore fruit, shortly after harvest. (It's advisable to dispose of all clippings, either by burning or taking to the dump. Dead canes can spread disease.)
  2. In the early spring, thin the canes to about five to seven per plant.
  3. Also in the spring, prune back side branches on the remaining canes to about 12 inches long, containing roughly 12 buds. This "tip-pruning" will encourage the plant to branch out, leading to more fruit. Make sure to use sharp cutting tools for this.
  4. Tie the pruned canes to the fencing.
  5. In summer, routinely inspect and remove any dead, diseased, or broken canes that you find.

Pruning Tips

  • For new raspberry plants, prune back the canes to 4 to 5 feet tall during the first few years. This will ensure that the bush gets plenty of light, which is essential to fruit production. It also makes harvest easier if you keep the canes at a reasonable height.
  • When planting new blackberry plants, pinch or prune off the growing tips of all new canes to encourage side shoots (laterals). This is where next season's blackberries will grow.
  • There are some modern blackberry varieties that are virtually thornless and they make pruning a lot less hazardous.
  • One form of raspberry is called a "black raspberry." This is not the same as a blackberry, and it should be pruned as any other raspberry.