I've been filling my yard with seaweed, and when it's bedded down and thoroughly washed by rain so there's no salt left I want to cover it with sand/soil and plant grass (or similar ground-covering plant). Can anyone suggest the best way to do this, and what varieties I should consider? I want something that has good dense cover, doesn't need constant watering (once it's established), will withstand the influx of weeds and other vegetation, and is self-limiting on growth so it doesn't need frequent cutting. Back in Britain I know there are varieties that will do all this, but what about here?