Do Thornless Blackberry Bushes Spread

Thornless blackberry bushes do spread, and they can spread quite aggressively once they’re established.
 
That surprises a lot of gardeners who assume “thornless” also means “well-behaved.”
 
If you’ve been asking yourself, “do thornless blackberry bushes spread,” the short answer is yes, and understanding how they spread is the key to keeping them under control.
 
Thornless blackberry bushes spread mainly through their root systems and through tip layering, where the canes bend down and root wherever they touch the soil.
 
In this post, we’ll look at why thornless blackberry bushes spread, how far they can travel, and the best ways to keep them contained so they don’t take over your whole yard.
 
Let’s dig in.
 

Why Thornless Blackberry Bushes Spread

Thornless blackberry bushes spread for the same reason their thorny cousins do.
 
It’s simply in their nature as vigorous perennial plants.
 
Here’s why they spread so readily.
 

1. They Grow From Perennial Root Systems

The biggest reason thornless blackberry bushes spread is their perennial root system.
 
While the canes themselves are biennial, the roots live on year after year.
 
Those roots constantly send up new shoots, called suckers, sometimes several feet away from the main plant.
 
This means even if you cut every cane to the ground, the thornless blackberry bush will bounce right back from the roots.
 

2. Tip Layering Sends Canes Underground

Thornless blackberry bushes also spread through a clever trick called tip layering.
 
When a long cane arches over and touches the ground, the tip starts to root right there.
 
A whole new thornless blackberry bush forms at that spot, still connected to the parent plant.
 
Left alone, one plant can create a whole thicket this way in just a couple of seasons.
 

3. They Send Out Underground Runners

Many thornless blackberry varieties also send out underground runners, also known as rhizomes.
 
These runners travel beneath the soil and pop up as new plants far from the original bush.
 
This is why thornless blackberry bushes often show up in spots where you never planted them.
 
And it’s a big reason why they’re considered invasive in some regions.
 

4. Birds and Wildlife Spread the Seeds

On top of root spread, thornless blackberry bushes spread through seed too.
 
Birds love the berries and drop the seeds far and wide.
 
Those seeds sprout into new thornless blackberry bushes, sometimes in the wild and sometimes right in your neighbor’s garden.
 
So even a single bush can slowly colonize a much wider area over time.
 

How Far Do Thornless Blackberry Bushes Spread?

Thornless blackberry bushes spread further than most people expect.
 
Underground runners can travel several feet in a single growing season.
 
Tip layering can add new plants right beside the parent, and those plants then spread even further the next year.
 
A well-established thornless blackberry bush can expand its patch by three to six feet annually in good conditions.
 
Over a few years, that same plant can form a dense thicket that’s tough to remove once it’s settled in.
 

How to Keep Thornless Blackberry Bushes From Spreading

The good news is you can enjoy thornless blackberry bushes without letting them run wild.
 
You just need a little planning and regular maintenance.
 
Here’s how to keep them in check.
 

1. Plant Them in Raised Beds

Raised beds or large containers create a physical barrier that slows down spreading.
 
A thornless blackberry bush in a pot won’t be able to send runners into the surrounding soil.
 
Just make sure the container is big enough, since these plants have large root systems.
 

2. Install Root Barriers

If you’re planting in the ground, bury a root barrier around the bed.
 
A sturdy piece of metal or thick plastic set 12 to 18 inches deep will stop most runners.
 
This keeps your thornless blackberry bushes from creeping into the lawn or garden beds.
 

3. Prune and Remove Suckers Regularly

Regular pruning is one of the simplest ways to control thornless blackberry bushes.
 
Cut back any suckers that pop up outside the main row.
 
Trim long canes before they tip over and root.
 
Staying on top of this every few weeks during the growing season makes a huge difference.
 

4. Mow Around the Patch

Mowing the perimeter around your thornless blackberry bushes keeps stray shoots from taking hold.
 
Any sucker that pops up in the lawn gets chopped before it can establish roots.
 
It’s an easy habit that stops spreading before it ever gets out of hand.
 

So, Do Thornless Blackberry Bushes Spread?

Thornless blackberry bushes do spread, and they do it through root runners, tip layering, and seeds dropped by birds.
 
They’re vigorous plants, and while that vigour means bigger harvests, it also means you’ll need to keep an eye on them.
 
Plant them in raised beds, add root barriers, prune regularly, and mow around the patch to keep spreading in check.
 
Do that, and your thornless blackberry bushes will reward you with plenty of fruit without swallowing the yard.