One of my favorite articles from Permaculture magazine is John Walker's use of cardboard to tame weeds in an allotment garden.
http://www.permaculture.co.uk/...
I am trying this now in my overgrown Alabama yard. Its an excellent way to use up all that cardboard that accumulates from internet shopping. Don't give it to city sanitation to haul away. It can help you reclaim your back 40!