How And When To Prune Thornless Blackberries

How and when to prune thornless blackberries is one of those things that seems complicated until you actually understand what the plant needs.
 
The best time to prune thornless blackberries is late winter or early spring while the plants are still dormant, before new growth starts pushing out.
 
And the how is simpler than you’d think once you know your blackberry type and what to cut back.
 
If you’ve been wondering how and when to prune thornless blackberries so they stay productive year after year, you’re in the right place.
 
In this post, we’ll walk through exactly when to prune thornless blackberries, how to prune thornless blackberries step by step, and the mistakes that ruin next year’s harvest.
 
Let’s dig in.
 

When to Prune Thornless Blackberries

When to prune thornless blackberries really comes down to two windows: dormant pruning and summer tipping.
 
Both matter, but they do different jobs for the plant.
 

1. Late Winter Dormant Pruning Is the Main Event

The primary time to prune thornless blackberries is late winter, usually February or early March depending on where you live.
 
Your plants should still be dormant, meaning no new buds or leaves have opened yet.
 
Pruning thornless blackberries at this stage wakes them up ready to push strong, healthy canes instead of wasting energy on dead wood.
 
If you prune too early in a cold climate, you risk dieback from frost damage.
 
Prune too late, and you cut away the new growth that would have produced this year’s berries.
 

2. Summer Tipping Keeps Them Manageable

You can also prune thornless blackberries lightly in summer.
 
This is called tipping, where you pinch or snip off the top few inches of new canes.
 
Tipping encourages side branches that carry more fruit the following season.
 
It also stops the canes from growing out of control and flopping over your garden path.
 

3. Prune After Harvest to Remove Old Canes

Right after you finish picking berries, you can prune thornless blackberries again by cutting out the canes that just fruited.
 
Those floricanes won’t produce again, so leaving them just invites disease and clutters the row.
 
This isn’t a heavy prune, just cleanup that helps air move through the plant.
 

How to Prune Thornless Blackberries the Right Way

Now that we’ve covered when to prune thornless blackberries, let’s talk about the how.
 
Since these plants don’t have thorns, the job is honestly a lot more pleasant, but the rules stay the same.
 

1. Know Your Canes: Floricanes vs. Primocanes

Thornless blackberries grow two types of canes.
 
Primocanes are the new first-year canes that only grow leaves.
 
Floricanes are second-year canes that actually bear fruit.
 
When you prune thornless blackberries, you’re mainly removing spent floricanes and thinning primocanes so the plant doesn’t choke itself out.
 

2. Cut Out Dead, Diseased, and Spent Canes First

Start by cutting every dead, broken, or diseased cane right at ground level.
 
Then remove the floricanes that already fruited this past season.
 
They usually look brown and woody compared to the fresher green or reddish primocanes.
 
Getting these out first makes it way easier to see what’s left to work with.
 

3. Thin the Primocanes to 4-6 Per Plant

Healthy thornless blackberries throw out way more canes than they need.
 
Keep the strongest four to six primocanes per plant and cut the rest to the ground.
 
Space them out so air can move freely between them.
 
Thinning like this is how you prune thornless blackberries so they produce bigger, sweeter berries instead of a mess of small ones.
 

4. Trim Side Branches on Trellised Canes

If you grow them on a trellis, cut side branches back to about 12 to 18 inches.
 
This concentrates the plant’s energy and keeps the row neat.
 
When you prune thornless blackberries this way, the side shoots become the fruiting wood for the next season.
 

5. Tip the New Canes in Summer

Around midsummer, snip the top two to three inches off each new primocane.
 
That forces the cane to branch out lower down.
 
And that means more places for berries to form next year.
 

How and When to Prune Thornless Blackberries in Different Climates

Your location shifts the calendar a bit when you prune thornless blackberries.
 
In warm southern zones, dormancy ends earlier, so late January often works better than March.
 
In colder northern zones, wait until the worst of the freeze has passed, usually late March or even early April.
 
If you’re ever unsure when to prune thornless blackberries, look at the plant itself.
 
If the buds are still tight and closed, you’re fine.
 
If green tips are already opening, you’ve waited too long.
 

Common Mistakes to Avoid

Cutting everything to the ground is the biggest mistake people make.
 
That kills off the floricanes that would have fruited this year.
 
Another common slip is pruning thornless blackberries too early in fall, which triggers new growth that winter kills.
 
And skipping the summer tipping means long, skinny canes that snap under the weight of fruit.
 

So, How and When to Prune Thornless Blackberries?

How and when to prune thornless blackberries really comes down to timing and technique.
 
Prune thornless blackberries in late winter while they’re dormant, tip new canes in summer, and clean up spent floricanes right after harvest.
 
If you follow these steps, you’ll prune thornless blackberries with confidence and enjoy a bigger, sweeter crop every single year.