Oh-convolvulus-a natural spray-I wish! I haven't found anything in the more than 10 years I've been fighting it. I find the best method is dig out the roots and leave them to dry and die in the hot sun. Then attck every new sprout you see. But I haven't ever managed to get rid of it all as we have a lot! I can keep it under control where I'm gardening though. I've tried smothering it, but it doesn't work.