Will Weed Killer Kill Blackberry Bushes

Weed killer can kill blackberry bushes, but getting rid of these stubborn plants is rarely as simple as spraying once and walking away.
 
Blackberry bushes are tough, invasive, and incredibly resilient, so most regular weed killers won’t do the job on their own.
 
If you’ve been battling blackberry bushes in your yard and wondering whether weed killer will finally put an end to them, you’re in the right place.
 
In this post, we’ll look at whether weed killer will kill blackberry bushes, which types actually work, and how to apply them so the bushes don’t come roaring back.
 

Will Weed Killer Kill Blackberry Bushes?

Weed killer can kill blackberry bushes, but only if you choose the right product and apply it correctly.
 
Here’s what you need to know about making weed killer work on blackberry bushes.
 

1. Not All Weed Killers Are Created Equal

Most general-purpose weed killers you grab off the shelf are designed for soft, leafy weeds, not woody shrubs like blackberry bushes.
 
To actually kill blackberry bushes, you need a systemic herbicide that gets absorbed into the plant and travels down to the roots.
 
Contact weed killers only burn the leaves you spray, leaving the roots alive and ready to send up new canes within weeks.
 

2. Glyphosate and Triclopyr Are the Heavy Hitters

Products containing glyphosate or triclopyr are the most effective weed killers for blackberry bushes.
 
Glyphosate works well but is non-selective, meaning it will kill anything green it touches, so you have to be careful around your garden.
 
Triclopyr is often the better choice for blackberry bushes because it targets woody plants and broadleaf weeds while leaving most grasses alone.
 

3. Timing Matters More Than You Think

The best time to apply weed killer to blackberry bushes is in late summer or early fall, when the plant is actively moving nutrients down to its roots.
 
Spraying during this window means the herbicide gets pulled deep into the root system, which is exactly where you need it to kill blackberry bushes for good.
 
Spring spraying can work too, but it’s usually less effective because the plant is pushing energy upward instead of down.
 

4. One Spray Is Almost Never Enough

Even with the right weed killer, killing blackberry bushes usually takes more than a single application.
 
You’ll typically need to spray, wait a few weeks for the canes to die back, and then spray any new growth that pops up.
 
Patience is key here, because blackberry bushes store a lot of energy in their roots and can regrow from small surviving pieces.
 

How to Apply Weed Killer to Blackberry Bushes

Getting weed killer to actually kill blackberry bushes comes down to how you apply it.
 
Here’s the approach that works best.
 

1. Cut the Canes Back First

Before you spray, cut the blackberry bushes down to a few inches above the ground.
 
This stresses the plant and forces it to push out new growth, which gives you fresh leaves to spray.
 
Just don’t cut them all the way to the soil, since the regrowth is what absorbs the weed killer.
 

2. Spray the New Growth Thoroughly

Once new leaves appear, spray them evenly with your chosen weed killer until they’re wet but not dripping.
 
Don’t forget the underside of the leaves, since that’s where absorption happens most efficiently.
 
And always spray on a calm, dry day so the weed killer doesn’t drift onto plants you want to keep.
 

3. Protect Nearby Plants

Since many weed killers that kill blackberry bushes are non-selective, shield your other plants with cardboard or plastic sheeting while you spray.
 
You can also apply the herbicide with a paintbrush or sponge directly onto the cut canes for more precision.
 
This cut-and-paint method is slower, but it’s a great option when blackberry bushes are growing close to ornamentals or vegetables.
 

4. Repeat Until the Roots Give Up

After the first round, wait about three to four weeks and check for regrowth.
 
Spray any new shoots that appear, and keep repeating this cycle until nothing comes back.
 
For really established blackberry bushes, this back-and-forth can take a full growing season or more.
 

5. Combine Weed Killer With Digging

If you want to speed things up, combine weed killer with manual removal.
 
Once the canes are dead, dig out the root ball and any thick rhizomes you can find.
 
This one-two punch is often the fastest way to kill blackberry bushes, especially in small yards where digging is manageable.
 

Common Mistakes When Using Weed Killer on Blackberry Bushes

A lot of people spray once, see the leaves die, and assume the blackberry bushes are gone.
 
Then a month later, new canes shoot up from the roots and the whole cycle starts over.
 
Another common mistake is spraying in the heat of summer when the plant is drought-stressed, which makes the weed killer less effective.
 
And skipping the cut-back step means you’re spraying old, tough leaves that don’t absorb the herbicide nearly as well.
 

So, Will Weed Killer Kill Blackberry Bushes?

Weed killer can kill blackberry bushes, but only if you use a systemic product like glyphosate or triclopyr and apply it at the right time.
 
One spray usually isn’t enough, so plan on cutting the canes, spraying the regrowth, and repeating until the roots finally die.
 
Combine that with a little digging and you’ll win the battle against those stubborn blackberry bushes for good.