Posted: 24/05/2012 at 09:57
There's not much you can do to neutralize the urine other than copious amounts of water, unfortunately. If your clematis is in a pot, you could try re-potting it.
As for the base problem - the dogs are marking their territory. One solution might be to put something very strong-smelling where they are marking - I've no idea if garlic would work, but it might be worth a try.
On the electronic front, I would try a cat scarer - dogs hear in the same range, so it should work against them. I wish you the best of luck - this is a very unpleasant (and smelly) problem.