Try the search box Gralew, if you put pampas grass in then you get all the mentions, maybe one will be the one you want

Thanks Pam, I was so sure that i'd put in favs. Will try the search box.

I don't know who answered you originally, but I'll give the answer anyway. If you live somewhere where you're allowed to, and the plant isn't close to a fence or anything that might burn, use a flame thrower on it. Otherwise, cut off everything, meaning the leaves right back to the central stump, then clip off as near their bases as you can any flowered stems, then rake out the centre of the stump. So you'll need sharp shears, a pair of loppers for the flowering stems, and a small rake or hand held tool to rake out the centre. And also protective clothing which covers your arms, a pair of gloves to protect your hands, and preferably some form of eye protection, because the leaves are unpleasant to handle. Best done in Spring, so March in the South, probably a bit later in the North.