Those fake wasp nests you can get to deter them actually work but you have to put them up early in the wasp season or they won't! I had one years ago but obviously put it up too late and it had no effect but my new one has been up just over a week and I've seen one wasp in all that time when my garden was full of them before. They ruin my time in the garden every summer and I know there are others in the same boat so just thought I'd pass on what I've learned. So if you want to give it a try get cracking while the horrible stripy bastards are still out looking for nest sites, they will give your garden a wide berth if they think a nest is already there!