Will a Weed Burner Kill Blackberry? The Honest Answer
We get asked this a lot, usually by someone standing in front of a thicket that's been there longer than they've owned the place. So here's the honest answer rather than the one that sells more burners.
No. A weed burner will not kill an established blackberry. Not in one go, not in an afternoon, not with more BTUs.
But that's not the end of the story, because it does have a genuine job in a blackberry program — it's just not the job people imagine.
Why it doesn't work on its own
A weed burner kills by rupturing plant cells with a burst of heat. Whatever is above the ground dies. Whatever is below it doesn't even notice.
Blackberry has three things going for it underground, and all three are out of reach:
- A woody root crown that's been storing energy for years. Older, bigger crowns are hard to kill by any method.
- Lateral roots that sucker. Damage the top and it can push new shoots up somewhere else entirely.
- Cane tips that strike root wherever they touch the ground, so one plant quietly becomes a dozen.
So you take the leaves off with a burner and the crown simply spends a bit of its savings and grows them back. You've inconvenienced it. You haven't beaten it.
Worth saying plainly: this isn't a flame problem, it's a blackberry problem. Digging doesn't fix it either, because you'll never get every root fragment out, and any bit left behind reshoots. Blackberry is a multi-season job with every method. Anyone who tells you they've got a one-hit solution is selling something.
Where a burner genuinely earns its keep
Three jobs, and they're all real.
1. Seedlings, on sight
A blackberry seedling is a soft little thing with nothing stored underground yet. Hit it and it's dead, same as any annual weed. Every seedling you kill this year is a crown you're not fighting in five years' time. If you've cleared a patch, walking it every few weeks and knocking over the new ones is the cheapest hour you'll spend.
2. Starving the crown after cutting
This is the one that actually works on established plants, and it's a war of attrition rather than a battle.
Cut or slash the thicket down. The crown responds by pushing out soft new regrowth, and to do that it spends stored energy. Then, before that new growth has time to photosynthesise and pay the crown back, you take it off again. And again. And again.
Every cycle, the crown is a bit further into the red. Keep it up consistently and eventually it runs out. Flame is well suited to this stage because the regrowth is soft and young, and because you can do it quickly without dragging a slasher back in.
The critical word there is consistently. Irregular knocking-back is actively counterproductive — you end up with a plant that has a strong root system and almost no top growth, which is the hardest thing in the world to treat by any method. Half-doing this is worse than not starting.
3. Holding a cleared boundary
Once you've cleared ground, blackberry will try to walk back in from the edges — from a neighbour's fenceline, a creek, a road reserve. Running a burner along that boundary a few times a season keeps the front line where you put it.
What we'd tell you if you rang us
If you have a couple of acres of established blackberry thicket and you're hoping a weed burner will clear it, we'd tell you not to buy one for that. It won't do what you want, and we'd rather say so now than process a refund later.
If you've got blackberry that you're already cutting or slashing, and you want a chemical-free way to keep hammering the regrowth — particularly near a dam, a house, a vegie patch or animals, where you don't want to spray — then a burner fits that job well.
And if you're at the stage where it's mostly seedlings and creeping edges, a burner is genuinely the right tool and you'll stay on top of it easily.
One thing to check before you start
Blackberry is a declared weed across most of Australia and in a lot of areas you have a legal obligation to control it. That cuts both ways: it means you can't just ignore it, but it also means your council or Landcare group may have advice, programs or even assistance available. Worth a phone call before you spend a season on it alone.
And whatever you use, check current fire restrictions before you put a flame anywhere near dry blackberry canes. Dead cane is fuel.
Short version
Won't kill an established crown. Kills seedlings outright. Genuinely useful for repeatedly knocking back regrowth after cutting, which is the method that actually beats blackberry over a few seasons. Buy one for that job and you'll be happy. Buy one expecting to clear a thicket in a weekend and you won't be.
We've written up the same honest verdict for a dozen other weeds — have a look at the weed-by-weed guide, or ring us on +61 449 268 131 and just tell us what you're looking at.