Raspberry plants spread by suckers. This means raspberries like to grow and will spread out far and wide if you let them. But large, unpruned raspberry bushes won't yield more berries and can lead to problems and even early die out of the raspberry bushes. Pruning raspberry plants do more than just keep your plants under control. Raspberries can be prone to disease and pruning inhibits the spread of disease throughout your patch.
To ensure that light and air can get inside the plants and to facilitate pruning, keep your raspberry 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 the 12 to an 18-inch footprint. Don't worry, the bushes will be much larger on top.
What Kind of Raspberry Are You Pruning?
There are two bearing categories for raspberry plants:
- Summer Bearing (floricane) Raspberries will provide 1 large harvest, usually in late summer or early fall. Summer-bearing raspberries bear fruit on 2-year-old canes, the canes 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 2 harvests per season; one in mid-late summer and one in the fall. They fall crop will probably be a bit lighter and is on 1-year-old canes of the current season. Many fall bearing raspberries bear so late in the fall that they are not practical for gardeners in short season climates.
How and When to Prune Raspberries
A word of caution: Wear thick gloves because raspberries have serious thorns, and always use clean, sharp tools.
LATE WINTER & EARLY SPRING (Before Bud Break)
- Prune all canes that bore fruit last year; they won't fruit again. These will have grayish, peeling bark.
- Remove any canes that have grown outside the 12 to 18-inch designated row footprint.
- Remove any spindly or short canes.
- Thin so that there are about 4 to 5 of the healthiest, tallest, and fattest canes left per foot along the length of the row.
- Tie remaining canes to your fencing.
- To force your everbearing raspberries to produce only one crop in the fall, prune back the entire raspberry bush in early spring. 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 is good if you also have summer-bearing raspberry bushes and you want to stagger the harvests.
- Prune dead, broken, or diseased canes.
- Prune any canes that poke up outside your designated row area.
Of course, you can prune broken, dead, diseased, or infested canes at any time of the year. The sooner, the better.
Why Prune Blackberries?
Pruning blackberries is an even less complicated procedure, except for the thorns. Here are some tips on pruning blackberry plants.
Blackberries aren't quite as enthusiastic growers as raspberries, but they will yield better with regular pruning. And as with raspberries, they can be prone to diseases that spread rapidly in unmaintained plants.
How and When to Prune Blackberries
Blackberries can also have dangerous thorns. Gloves are recommended and clean, sharp tools are also necessary. There are some modern blackberry varieties that are virtually thornless and they make pruning a lot less hazardous.
Newly Planted 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.
Maintaining Bearing Blackberry Plants
- 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.)
- Thin canes to about 5 to 7 per plant.
- Prune side branches on remaining canes to about 12 inches or 12 buds.
- Tie the pruned canes to your fencing.
As with raspberry plants, you can prune broken, dead, diseased or infested canes at any time of the year, the sooner the better.
Pruning raspberries take a little more thought, but it's still worth the effort. Here are the steps for pruning raspberry plants for a better harvest.