The groundcover had blown off the bed where the sweetcorn were last year.There is only one small weed in evidence to the side of the bed. Considering the amount of horsetail in some of the other uncovered areas of the plot I think this says a lot for the benefits of ground cover. Before I made the new bed I dug a large amount of horsetail out of the area so there must have been a fair bit left. The groundcover has kept it in check.