When To Cut Back Thornless Blackberry Bushes

The best time to cut back thornless blackberry bushes is during their dormant season, typically in late winter or early spring before new growth begins.
 
Pruning thornless blackberry bushes at the right time keeps them productive, healthy, and easy to manage.
 
If you prune too early or too late, you risk damaging the canes and reducing your harvest.
 
In this post, we’ll walk through exactly when to cut back thornless blackberry bushes, how to do it properly, and the common mistakes to avoid.
 
Let’s dig in.
 

When to Cut Back Thornless Blackberry Bushes

Knowing when to cut back thornless blackberry bushes comes down to understanding their growth cycle.
 
Thornless blackberries produce fruit on canes that are one year old, called floricanes.
 
Those floricanes die after fruiting, while new primocanes grow to produce next year’s crop.
 
That’s why timing your pruning correctly matters so much.
 

1. Late Winter Is the Sweet Spot

Late winter, usually February or early March depending on your climate, is the ideal time to cut back thornless blackberry bushes.
 
At this point, the plants are still dormant, so pruning won’t shock them.
 
You can clearly see which canes are dead, damaged, or diseased without leaves getting in the way.
 
Cutting back thornless blackberry bushes now also sets them up for strong spring growth.
 

2. Early Spring Works Too

If you miss late winter, early spring is your next best window to cut back thornless blackberry bushes.
 
Just make sure you prune before new buds break and start leafing out.
 
Once the plant is actively growing, pruning can sap its energy and reduce fruit production.
 
So aim to finish cutting back your thornless blackberry bushes before that growth spurt kicks in.
 

3. Avoid Pruning in Late Spring or Summer

You generally shouldn’t cut back thornless blackberry bushes in late spring or summer unless you’re just removing a dead or broken cane.
 
Pruning during the growing season stresses the plant and can expose fresh cuts to pests and disease.
 
Summer pruning also removes the very canes that would carry next year’s berries.
 
So hold off on major cuts until dormancy returns.
 

4. Fall Pruning Is a Big No-No

Fall might seem tempting because the plant looks finished for the year, but cutting back thornless blackberry bushes in autumn is risky.
 
Pruning wounds won’t heal before cold weather hits, leaving the plant vulnerable to winter damage.
 
Wait until the coldest part of winter has passed, then cut back thornless blackberry bushes with confidence.
 

How to Cut Back Thornless Blackberry Bushes Properly

Once you know when to cut back thornless blackberry bushes, the next step is doing it right.
 
Here’s how to tackle the job:
 

1. Remove Dead and Diseased Canes First

Start by cutting out any canes that are dead, broken, or showing signs of disease.
 
These canes won’t produce fruit and can spread problems to the rest of the plant.
 
Cut them right at the base, close to the ground.
 

2. Thin Out Crowded Canes

Thornless blackberry bushes need good airflow to stay healthy.
 
Thin out canes so they’re spaced about 4 to 6 inches apart.
 
This reduces the chance of fungal issues and makes harvesting easier.
 

3. Tip the New Primocanes

For trailing varieties, tip the new canes in summer to encourage branching.
 
For erect varieties, you can cut them back to about 3 to 4 feet tall during dormancy.
 
This keeps your thornless blackberry bushes manageable and productive.
 

4. Dispose of Debris

After you cut back thornless blackberry bushes, clean up all the clippings.
 
Don’t leave diseased canes lying around the garden.
 
Burn them or bag them for trash pickup to prevent pests and disease from spreading.
 

Common Mistakes When Pruning Thornless Blackberry Bushes

Even with the best intentions, gardeners often slip up when cutting back thornless blackberry bushes.
 
Here are a few pitfalls to dodge:
 

1. Pruning at the Wrong Time

The biggest mistake is cutting back thornless blackberry bushes too early or too late.
 
Prune in dormancy, not during active growth, and you’ll avoid most problems.
 

2. Cutting Too Much or Too Little

Over-pruning weakens the plant, while under-pruning leads to a tangled mess and poor fruit.
 
Aim for balance: remove old floricanes and thin the rest.
 

3. Ignoring the Cane Age

Thornless blackberries fruit on second-year canes, so never cut those back by mistake.
 
Learn to tell the difference between floricanes (brown, woody) and primocanes (green, fresh).
 

So, When to Cut Back Thornless Blackberry Bushes?

The best time to cut back thornless blackberry bushes is late winter or early spring during dormancy, before new growth starts.
 
Pruning at the right time keeps your plants healthy, boosts fruit production, and makes them easier to manage.
 
Avoid fall and summer pruning, and always remove dead or diseased canes first.
 
With a little patience and the right timing, your thornless blackberry bushes will reward you with a bountiful harvest year after year.