I have about 70 to 100 tansy ragwort plants in a newer 30 acre pasture. I sprayed last week with round up, it got about half of them. They haven't flowered yet and I don't want to just pull or dig them up I want to "fry the roots"! I have plenty of good pasture left without tansy, so I can leave the cattle out of it for a few weeks. I have worked hard to get rid of most of the bracken but the tansy worries me a little more. Again I want to spray not dig our pull. I spraied for canadian thistle, Curtail controls the thistles great. Has anyone tried Curtail on ragwort?