Yesterday while moving a chair in my garden I got stung by a group of wasps. During the night I went hunting for their nests and managed to neutralize 3 of them: one was in the chair's legs, about the size of a child's fist and with a dozen on them inside. It was made of grey hexagonal cells, similar to paper in appearance.
Then I've found another one in a water hose tube that was slightly smaller, but quite active.
And finally a third one in a vase, it was very small, only had a couple of cells in it and wasps were working on it, almost as if they were building it from scratch.
Given the number and size of the nests I'm afraid that they could be spreading in the garden. I have already noticed that a couple of them survived the massacre of last night and I'm worried that unless I kill every of them they might keep nesting.
I don't know much about the hierachical society of wasps, but I was not able to identify the queen (although I haven't checked every single one I've killed). Reading online I've found that killing the queen might mean that the worker would eventually die.
So what kind of wasp is this? What can I do to make sure that they do not keep bothering me?
EDIT: by the way, I live in northern Italy