Make a wasp trap outside the window - either on the ledge or further away if you can
You'll need an old jam jar, preferably with a little jam still left in the bottom.

The important thing is to put some tin foil over the top, fasten it with an elastic band and punch some holes in it with a pencil. That last bit is the main bit - wasps cannot fly upside down (unlike bees apparently) so they try to come out and are faced by jagged bits of foil...bees will simply rotate themselves and buzz out and away. The wasps will be trapped - you can also put some water in the bottom so it's a sticky goo that they can drown in.

This also works well for fruit trees - plum trees in particular - hang these traps around the tree and the wasps will keep of your lovely succulent plums!

I think I heard this tip on Gardeners' Question Time - yes, I am that sad.
( chickenlady b3ta's very own Elizabeth Taylor, Wed 13 Aug 2008, 16:54, Reply)