Will a Weed Burner Kill Paterson's Curse? Mostly Yes, With One Catch
Paterson's curse — Salvation Jane if you're from South Australia, and there's a story in that name difference — is one of the weeds we get asked about most by people running horses.
Short answer: yes, a weed burner kills it, and autumn is when you want to be doing it. There's one catch worth knowing about, and it's about size.
How the plant works
Paterson's curse is an annual, sometimes biennial. It germinates with the autumn break, then sits through autumn and winter as a big flat rosette of hairy leaves pressed against the ground, smothering whatever's underneath it. In spring it throws up the purple flower stalks everyone recognises, sets a huge amount of seed, and dies.
At the rosette stage almost everything it owns is sitting above ground in plain sight. That's the window.
The catch: the taproot
Here's the bit that separates this from something like capeweed. Paterson's curse builds a stout taproot as the rosette gets bigger. That's part of why it competes so hard and why it survives a dry spell that kills other things.
What that means practically:
- Seedlings and small rosettes — killed outright. Nothing stored downstairs yet.
- Big established rosettes — you'll take the leaves off, but a well-developed taproot can push new growth back up. Expect to go over those a second time a few weeks later.
None of that is a reason not to do it. It's a reason to go early. The same paddock that takes two passes in July would have taken one in April.
Once it's purple, you've missed it
By the time you're looking at a paddock of purple flowers, the plant has already done its job. You can still kill it, and there's some value in stopping it topping up the seed bank further, but the seed already in the ground will be back next autumn regardless.
Paterson's curse seed is famously persistent in soil. This is a multi-year job, and the way you shorten it is by never letting plants flower, not by working harder in spring.
Why people use flame for this one
Nearly everyone who rings us about Paterson's curse has horses.
The plant contains pyrrolizidine alkaloids, which cause cumulative liver damage. Horses and pigs are the most sensitive; cattle and sheep are more tolerant but not immune, and chronic low-level exposure over a season is the usual pattern rather than one dramatic poisoning. As with fireweed, drying it doesn't make it safe — contaminated hay carries the problem straight into the feed shed.
Given that, a lot of owners simply don't want to spray a paddock their horses live in. With a burner there's no withholding period, no re-entry time, and nothing to keep animals off afterwards. You treat it and the paddock is exactly as it was five minutes earlier, minus the weed.
If you're worried an animal has been getting into it, that's a vet conversation.
Technique
- Autumn, straight after the break. Walk the paddock as soon as the rosettes appear. That's the cheapest pass you'll ever do.
- Brief contact is enough. You're not incinerating it. Dark, glossy, wilting leaves means done.
- Go back over the big ones. Anything with a substantial rosette, plan on a second visit.
- Keep the ground covered. Paterson's curse gets its start in bare and overgrazed patches. Competitive pasture is the long game.
- Check fire restrictions before any open flame, every time.
Short version
Yes, with a size caveat. Small rosettes die on the spot. Big ones with a developed taproot may need a follow-up pass. Get in early in autumn and the job is easy; leave it until the purple shows and you're just tidying up while the seed bank tops itself up.
We've written the same honest verdict for a dozen other weeds — see the weed-by-weed guide, or ring us on +61 449 268 131.