Burn it, I've known it happily regrow from little bits that have
accidently arrived on our muck heap via the soil picked out of horses
hooves. It's the most incredible stuff, you've got to admire it's
ability to survive whatever we throw at it - so don't help it at all!

I think it has a very old genetic make-up, it's related to much larger
plants that flourished in the time of the dinosaurs. I suppose it has been
through some hard times to survive to the present day, which is maybe why it
is so persistent.

Andrew