Wasp Feeding Frenzy!

Dear Gardeners,

My mum gave me a cutting of a little tree she had, we are unsure of what it is.  Anyway we grew it patiently planted it out early last year and its doing well....However, I have just noticed that my lovely new tree is covered in big black aphids (biggest I have ever seen!) and their sticky butts have then attracted the wasps, and they are getting very numerous (see below pics).

Im not to worried about letting the wasps get on with it, but I don't want things to get too out of control.  I have a Jack Russell that likes to chase wasps and house 

flies for some reason (bees are safe) so as you can imagine its getting pretty hectic here.

So.....should I live with them and see what happens.....or do something to stop the swarm?

Any advice would be great, or if someone else has seen this before I would like to know the outcome

Many thanks

buuuzzzzzzzzzzzz