How To Keep Blackberry Bushes From Spreading

You can keep blackberry bushes from spreading by growing them in containers, installing root barriers, and staying on top of regular pruning. 

Blackberry bushes spread aggressively through underground runners and tip rooting, so if you don’t take steps to control them, they’ll take over your garden fast. 

The good news is that keeping blackberry bushes from spreading is totally doable with a few smart strategies. 

In this post, we’ll walk through how to keep blackberry bushes from spreading, including the best planting methods, barriers, and maintenance habits that actually work. 

Let’s dig in. 

Why Blackberry Bushes Spread So Aggressively

Before we jump into solutions, it helps to understand why blackberry bushes spread the way they do. 

Once you get this, keeping blackberry bushes from spreading becomes way easier to plan for. 

1. They Send Out Underground Runners

Blackberry bushes spread mainly through underground stems called rhizomes or runners. 

These runners travel horizontally beneath the soil and pop up as new plants several feet away from the mother plant. 

This is why a single blackberry bush can turn into a thicket in just a season or two. 

2. They Root at the Tips

Some varieties of blackberry bushes spread by tip rooting, which means the ends of their canes arch down, touch the soil, and grow new roots. 

Each of those new root points becomes an entirely separate plant. 

So even if you cut back the top growth, those rooted tips keep the spread going. 

3. Birds and Wildlife Help Them Travel

Birds eat blackberries and drop the seeds far and wide. 

That means blackberry bushes can spread beyond your property line without you doing a thing. 

While you can’t control the birds, you can control what happens inside your garden, which is where the next steps come in. 

How to Keep Blackberry Bushes From Spreading

Here are the most effective ways to keep blackberry bushes from spreading. 

1. Grow Them in Containers

One of the simplest ways to keep blackberry bushes from spreading is to plant them in large containers. 

Use a pot that’s at least 20 to 24 inches wide and deep, and fill it with a quality potting mix. 

The container walls stop those underground runners from traveling anywhere. 

Just make sure the container has good drainage, and place it where it gets full sun. 

2. Install a Root Barrier

If you want to grow blackberry bushes in the ground, a root barrier is your best friend. 

Dig a trench about 2 feet deep around the planting area and bury a thick, rigid barrier like galvanized metal or heavy-duty plastic. 

Leave about 2 inches of the barrier above the soil line so runners can’t climb over. 

This keeps blackberry bushes from spreading past the barrier while still giving them room to grow. 

3. Prune Regularly and Remove Suckers

Pruning is a big part of keeping blackberry bushes from spreading. 

Cut back the canes after they finish fruiting, and remove any suckers that pop up outside the main planting area. 

Don’t just cut them at the surface—dig down and pull out the runner too. 

If you only snip the top, the runner will send up a new shoot in no time. 

4. Use Landscape Fabric or Mulch

Landscape fabric around the base of your blackberry bushes can help stop runners from getting established. 

A thick layer of mulch on top also makes it easier to spot and pull new shoots. 

Just keep the mulch a few inches away from the canes so you don’t smother the plant itself. 

5. Mow Around the Perimeter

If your blackberry bushes are in a row or patch, mowing a wide strip around the perimeter can keep them from spreading into the lawn or other beds. 

Regular mowing cuts down any new shoots before they get a chance to root and grow. 

This is a simple habit that makes a huge difference over time. 

Mistakes That Let Blackberry Bushes Spread

Even with a plan in place, a few common mistakes can let blackberry bushes spread anyway. 

Here’s what to avoid. 

1. Skipping the Barrier Altogether

Planting blackberry bushes in open ground without a barrier is asking for trouble. 

Those runners will travel farther than you think, sometimes 10 feet or more in a single season. 

2. Ignoring Runners During the Growing Season

If you wait until fall to deal with runners, they’ve already had months to establish roots. 

Check for new shoots every couple of weeks during spring and summer. 

3. Letting Canes Touch the Ground

Tip rooting happens fast when canes are left to droop. 

Trellis your blackberry bushes or tie the canes up so they can’t reach the soil. 

This one step alone can dramatically reduce how much your blackberry bushes spread. 

So, How Do You Keep Blackberry Bushes From Spreading?

You can keep blackberry bushes from spreading by using containers, root barriers, regular pruning, and a bit of diligence during the growing season. 

Blackberry bushes spread through runners and tip rooting, so the key is stopping those runners before they get established. 

Stay consistent, check for new shoots often, and your blackberry patch will stay right where you want it.