Quite a few plotholders have been using woven black plastic landscape fabric to keep down weeds. If you use this, please ensure that the raw edges of this material are doubled under and held down by soil. Once the wind gets hold, the fabric flaps until it begins to unravel and yards and yards of plastic fibres are released. These are very dangerous to wildlife - easily entangling them and almost impossible to break - to say nothing of making a mess of the site.