How To Keep Blackberry Bushes Under Control

Keeping blackberry bushes under control is all about understanding how they grow and staying one step ahead of their spreading habit.
 
These plants spread through underground runners called rhizomes and through tip rooting, where canes bend to the ground and sprout new plants.
 
So when you ask how to keep blackberry bushes under control, the answer is a mix of smart planting, regular pruning, root barriers, and consistent maintenance.
 
If you ignore them for a single season, blackberry bushes can take over a garden bed, a fence line, or an entire corner of your yard.
 
The good news is that with a solid plan, you can keep blackberry bushes under control without losing your harvest or your sanity.
 
In this post, we’ll walk through practical ways to keep blackberry bushes under control, from choosing the right variety to cutting back unwanted growth.
 
Let’s dig in.
 

Why Blackberry Bushes Get Out of Control

Blackberry bushes get out of control because they’re built to spread, and they do it fast.
 
Understanding why they spread so aggressively is the first step to keeping blackberry bushes under control.
 

1. Rhizomes Spread Underground

Blackberry bushes send out underground stems called rhizomes that pop up as new plants several feet away from the main crown.
 
This means you can pull every visible cane and still find new blackberry bushes sprouting a month later.
 
That underground spread is the number one reason blackberry bushes get out of control so quickly.
 

2. Tip Rooting Creates New Plants

When blackberry canes grow long, their tips arch down, touch the soil, and root into brand new plants.
 
Each rooted tip becomes another blackberry bush that will produce its own canes and its own runners.
 
This is why a single blackberry bush can quietly turn into a thicket in just two or three seasons.
 

3. They Grow Fast and Tall

Blackberry canes can grow 10 to 20 feet in a single year, depending on the variety.
 
That rapid growth means blackberry bushes reach into pathways, fences, and neighboring beds before you realize it.
 
Fast growth plus underground spread is exactly why so many gardeners struggle to keep blackberry bushes under control.
 

How to Keep Blackberry Bushes Under Control

You can keep blackberry bushes under control by combining the right planting setup with regular pruning and root management.
 
Here are the most effective strategies.
 

1. Plant Them in Raised Beds or Containers

One of the easiest ways to keep blackberry bushes under control is to plant them in raised beds lined with landscape fabric or in large containers.
 
A physical barrier stops rhizomes from spreading into the rest of your yard.
 
Just make sure the container is at least 20 to 24 inches wide so the root system has room to grow.
 

2. Install Root Barriers

If you’re planting blackberry bushes in the ground, bury a root barrier at least 12 to 18 inches deep around the bed.
 
This stops underground runners from creeping outward and keeps blackberry bushes under control at the root level.
 
Check the barrier once a year and repair any tears or gaps before they become a problem.
 

3. Prune Twice a Year

Pruning is your best tool for keeping blackberry bushes under control.
 
In late winter, cut out all the canes that produced fruit the previous year, since those won’t fruit again.
 
In summer, tip back new canes to about 4 to 5 feet to stop them from arching and rooting into the soil.
 

4. Mow or Cut Back Volunteers

Any blackberry bushes that pop up outside your designated row should be mowed or cut at ground level immediately.
 
Don’t wait, because a young shoot can establish roots in just a couple of weeks.
 
Consistent mowing around the perimeter is one of the simplest ways to keep blackberry bushes under control long term.
 

5. Use Mulch and Ground Covers

A thick layer of mulch or a dense ground cover around your blackberry bushes makes it harder for stray runners to take hold.
 
It won’t stop rhizomes entirely, but it slows them down and makes new shoots easier to spot.
 

6. Train Them on a Trellis

Trellising your blackberry bushes keeps the canes upright and contained instead of sprawling across the ground.
 
When canes stay off the soil, they can’t tip root, which cuts down on new plants dramatically.
 
A simple T-trellis or two-wire system works well for most varieties.
 

Common Mistakes When Controlling Blackberry Bushes

Even with a plan, a few common mistakes can let blackberry bushes get out of control again.
 

1. Skipping Winter Pruning

If you skip winter pruning, old canes crowd the plant and new growth sprawls everywhere.
 
That makes blackberry bushes harder to manage and cuts down on fruit production.
 

2. Letting Canes Touch the Ground

Once a cane touches soil, it can root within weeks and create another blackberry bush.
 
Keep canes tied up and off the ground throughout the growing season.
 

3. Ignoring Runners Until Fall

By fall, those runners have already established root systems that are tough to remove.
 
Deal with new shoots as soon as you see them to keep blackberry bushes under control.
 

So, How Do You Keep Blackberry Bushes Under Control?

You keep blackberry bushes under control by blocking their roots, pruning twice a year, and removing volunteer shoots the moment they appear.
 
Blackberry bushes spread through rhizomes and tip rooting, so the key is stopping them before they establish new plants.
 
With raised beds, root barriers, trellises, and consistent maintenance, you can enjoy a healthy harvest without letting blackberry bushes take over your yard.
 
Stay on top of them each season, and blackberry bushes will stay right where you want them.