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The best time to prune thornless blackberries is in late winter or early spring while the canes are still dormant.
You should also know how to prune thornless blackberries in the summer to encourage more fruit production.
Pruning thornless blackberries isn’t complicated, but it does require a basic understanding of how the canes grow and produce fruit.
In this post, we’ll break down exactly when to prune thornless blackberries, how to prune thornless blackberries for maximum yield, and the common mistakes to avoid.
Let’s dig in and get your berry patch thriving.
When to Prune Thornless Blackberries
Knowing when to prune thornless blackberries is the first step to a healthy and productive plant.
The timing really boils down to two main seasons: winter dormancy and the summer growing period.
1. Late Winter to Early Spring (The Main Pruning)
The most important time to prune thornless blackberries is in late winter or very early spring, typically from February to early April depending on your region.
You want to do this while the canes are still dormant and before new growth begins to push out.
Pruning thornless blackberries during this window is ideal because it’s easy to see the structure of the plant without leaves in the way.
It also gives the plant a clean slate to put all its energy into the new canes that will bear fruit this season.
Just wait until the harshest cold snaps have passed, as pruning too early can leave cut ends vulnerable to frost damage.
2. Summer Pruning (After Fruiting)
The second key time to prune thornless blackberries is right after they finish fruiting in mid-to-late summer.
This is when you’ll remove the old floricanes, which are the canes that just produced berries.
These spent canes won’t fruit again, so you can cut them down to the ground to make room for the new primocanes.
Summer pruning also helps keep the patch from becoming a tangled mess and improves air circulation.
3. Tipping the Primocanes
Timing is also crucial for tipping, which means cutting the tips off the new green canes to encourage branching.
You should tip your primocanes in early summer when they reach about 3 to 4 feet tall.
This prompts the cane to send out lateral side branches, and those side branches are where the fruit will form next year.
So when you’re thinking about when to prune thornless blackberries, remember that tipping is a seasonal task that can’t be skipped.
How to Prune Thornless Blackberries for Maximum Yield
Now that you know the timing, let’s get into the actual technique of how to prune thornless blackberries.
It’s a straightforward process that gets easier every year once you understand which canes do what.
1. Identify Your Floricanes and Primocanes
First, you need to tell the difference between the two types of canes when you prune thornless blackberries.
The floricanes are the second-year canes that are brown, woody, and they’re the ones that will flower and fruit this year.
The primocanes are the first-year canes that are green, flexible, and they won’t fruit until next season.
You’ll always keep the primocanes and remove the floricanes after they’ve fruited.
This distinction is the heart of learning how to prune thornless blackberries correctly.
2. Cut the Spent Floricanes to the Ground
In late winter, you want to remove all the floricanes that already produced fruit last year.
Cut them off right at the soil line using sharp bypass pruners.
Because thornless blackberries have no thorns, you won’t need heavy gloves or long sleeves, which makes this job much more pleasant.
Removing these old canes is essential because they’re just dead weight now and can harbor pests or diseases.
3. Thin Out the Remaining Primocanes
Next, take a look at all the new primocanes that will carry next year’s fruit.
You don’t want to leave every single one, because overcrowding leads to poor air flow and smaller berries.
Aim to keep about 4 to 6 of the strongest, healthiest primocanes per plant.
Remove any that are thin, broken, or growing in a weird direction.
This thinning step is a crucial part of how to prune thornless blackberries for bigger, sweeter fruit.
4. Shorten the Lateral Branches
Once you’ve thinned the canes, you can also shorten the lateral branches on the floricanes you’re keeping.
Cut the side branches back to about 12 to 18 inches long.
This encourages the plant to produce larger berries rather than lots of tiny ones.
And for your primocanes, you can tie them to a trellis or wire system to keep them upright and organized.
Common Mistakes When Pruning Thornless Blackberries
Even with the best intentions, people make a few common errors when they prune thornless blackberries.
Avoiding these will keep your plants productive for many years.
1. Pruning All Canes in Winter
One of the biggest mistakes is cutting all the canes down to the ground in winter.
If you do that, you’ll remove all the floricanes that would have fruited this year.
Remember, you only remove the spent floricanes and keep the primocanes when you prune thornless blackberries.
2. Pruning Too Late in Spring
Another mistake is waiting too long to prune, until the new buds are already actively growing.
While it won’t kill the plant, late pruning can reduce the number of blossoms and berries.
That’s why the recommended time to prune thornless blackberries is while they’re still dormant.
3. Skipping the Summer Cleanup
Some folks only prune once a year, but skipping the post-fruiting cleanup is a big error.
If you leave the old floricanes in place, they’ll compete with new growth and create a dense, disease-prone thicket.
So make sure you get out there in July or August to clear away what’s done fruiting.
So, How and When to Prune Thornless Blackberries?
To sum it all up, you should prune thornless blackberries in late winter for the main structural cut and again in summer for cleanup.
And learning how to prune thornless blackberries isn’t hard, just keep the old canes out and the new canes in.
When you prune thornless blackberries with the right timing, you’ll be rewarded with a tidy plant and a heavy crop of delicious, hassle-free berries.
Whether you’re a brand new gardener or you’ve fought with thorny varieties for years, the process here is simple and forgiving.
Get your pruners ready, mark your calendar for late winter, and enjoy the satisfaction of a well-kept berry patch.