Blackberry bushes bear best and most abundantly when they’re properly pruned. Here’s how to prune blackberry bushes for the best harvest!
For those of us who grew up gathering loads of blackberries from wild-growing brambles, it may come as a surprise that blackberries yield the largest and best crops when they’re carefully pruned.
It wasn’t until after we bought our homestead and discovered a patch of wonderful, but long-neglected blackberry bushes, that I learned the importance of pruning blackberries, and how to do it properly.
To help understand the pruning process, it’s helpful to understand how blackberries grow and set fruit. They’re perennials, so they grow year after year, growing and spreading a bit each year.
While blackberry bushes grow year after year, their canes are biennial – this means they have a two-year life cycle. Blackberry canes do much of their growth during their first season, sending up a tall main cane, with lateral branches emerging from the sides. First-year blackberry canes are called primocanes.
In their second summer, most of a blackberry cane’s energy is spent on fruiting – establishing clusters of berries, which are primarily along lateral branches off the main canes. Second-year canes are called floricanes. When they’re done bearing a crop of berries, floricanes die back and won’t grow again.
Much of the task of blackberry pruning is about helping first-year primocanes grow in the best way to encourage the development of as many clusters of large berries as possible.
What you need for pruning blackberry bushes
Compared to pruning fruit trees, pruning blackberries is really pretty simple. It can be much more prickly, though! Whether thorny or thornless, it really helps to have the right tools when you’re taming a blackberry bush.
Unless you’re working with a thornless variety, prickles are a very real issue when pruning blackberry bushes. They’re sturdy, like rose thorns. You’ll want to wear long pants and sleeves, and rugged gloves.
Blackberry thorns are sharp and strong, so rose-pruning gloves are a great idea.
You’ll also need a good pair of well-sharpened loppers. I’m a huge fan of Fiskars’ 32″ power loppers. I use them for pruning absolutely everything, and they stand up to such a beating. I honestly can’t imagine growing fruit trees or bramble fruits without them.
While you could pretty much do all necessary blackberry pruning with a pair of loppers, I find it much more convenient to use a pair of hand shears for taking off the tips of tall canes, and trimming out any damaged side shoots. Again, I love my Fiskars, but really any strong and sharp pair of hand pruners will do.
When should blackberries be pruned?
In early spring, blackberries should be pruned as they’re emerging from dormancy. After the worst of winter, but before leaf break, is the best time. For us, that’s usually in April.
If you’re further south, this will be much earlier. To really see what a difference climate makes when it comes to the timing of blackberry care, check out these photos that my friend Chelsea and I took of our blackberries, on the same day! She’s in Florida, and I’m in Maine.
In the summer, blackberry canes should be “tipped” as they reach about 4′ high.
In the fall, it’s good practice to remove the current year’s fruiting canes, once they’re completely done bearing for the season.
Any time of year is right for removing damaged or diseased canes. If you notice something amiss with some of your canes, go ahead and trim them out right away.
Here’s how to prune blackberry bushes in the early spring:
Start by removing any dead or damaged canes. If you didn’t do a fall pruning, now is the time to remove all canes that bore last year. They’re very easy to distinguish from the canes that will bear this year’s berries. Old canes look brown and a bit shaggy. They also have bits of dried stems left from where last year’s berries grew.
Even if you did remove spent canes once they finished bearing last year, you’ll want to check for any that may have been killed or damaged by a tough winter. Only healthy, vigorous canes should remain.
Thin bushes to the best 4-6 canes. Remove the smallest, thinnest canes, and leave the most vigorous ones. This allows for better air flow, and helps the remaining canes to set a prolific amount of good-sized berries.
Now, make sure each cane is “tipped” back to about 4′ high. It’s best if you tip the canes back to about 4′ during their first year of growth, but if you didn’t do that last year, or missed some canes, go ahead and do it now. This will encourage more lateral growth.
Remove any very low side branches, anything lower than about 18″ from the ground. Berries growing this low will drape onto the ground, as they grow and weigh down the side shoots. Rather than allow them to set berries that will end up covered in dirt, attracting rodents, it’s better to remove them and allow the canes to put that energy into growing berries higher up.
Now, cut back the laterals (side branches on each cane) to 12-18″. If you’re training your blackberries to a trellis or fence, now is the time to go ahead and secure your canes to it.
Pruning blackberries in summer
By mid to late summer, you’ll want to keep your pruning shears handy. This is when you’ll start “tipping” first year-canes (primocanes) as they grow tall.
As each cane starts growing past 4 feet, go ahead ahead and prune it off at about 4′. Use that number as a rough guide – I’ve seen anywhere from 3′-5′ recommended, and I find that about 4′ works well for me. The goal here is to encourage as much robust lateral growth as possible.
When you make your cut, it’s best to do this at a slight angle, above a healthy lateral bud, with the slant angled away from the bud.
Because not all primocanes grow at the same rate, you’ll want to get out your pruning shears a few times during the season to stay on top of tipping the canes.
Pruning in the fall, after harvest
After the harvest has finished, you can go ahead and prune out all of the canes that bore fruit. They will not bear again, and the canes will die back to the ground.
Pruning dead, broken, and diseased canes
While there’s a real seasonal rhythm to the usual blackberry pruning tasks, damage-control pruning is something that can be done at any time of year, as soon as you notice the need.
Dead canes or broken-off branches can be cleanly removed.
Broken branches should be pruned cleanly below the break, since a clean cut is less prone to disease than a torn or jagged break.
Diseased canes should generally be removed right away, being careful to clean your pruning shears with alcohol afterward, to avoid spreading disease to healthy canes. One possible exception to this rule is blackberry cane blight, which may be most effectively controlled by waiting until winter to remove the infected canes (read this well-illustrated post to learn more about blackberry cane blight.) And for a good list of all diseases that affect blackberries, this site is helpful.
To quickly recap:
- In early spring, remove any dead canes or laterals, thin to 4-6 healthy canes per bush, remove laterals less than 18″ from the ground, and snip all laterals back to 12-18 inches.
- In summer, tip primocanes at 4′ to encourage lateral growth.
- In fall, remove floricanes after they’ve completely finished bearing.
That’s really all there is to pruning blackberries for bigger berries and larger crops. Good pruning also means that berries will be closer to the main canes, and easier to pick. I hope these tips for how to prune blackberry bushes come in handy, as you grow your blackberry patch, and work toward a wonderful harvest.
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