14/09/2014 at 16:24
The way I control creeping thistle is to fire it when in seed. Only the seeds burn and they do so in a flash. There's hardly any smoke, the thistle itself does not burn because it's wet and if done carefully, there's little likelihood of it spreading to a lower story. You need to be sensible about it and take sensible precautions. In other words don't go and fire a vast swatch beside a barn or something on a warm, breezy September's day.
This controls seed spread as no chemical will ever achieve.Done annually, and you weaken the plant. They'll disappear.