I would leave it alone. White faced hornets aren't all that common, and they are very interesting to watch. They can catch flies in flight. They are probably protecting your flowers from insects as well--in fact, your lovely garden could be what drew them there--an appreciative audience for all your work! Just don't go too near the nest or alarm them. If you have to go anywhere near the nest move very slowly and wear a protective hat in a dull color. Don't wear perfume or other fragrances near them. If you move carefully and slowly you can sit quietly about 10 feet from a nest and watch the goings on. Don't make any sound and move slowly when you leave as well. Also, they do pollinate to some extent. With the bee shortage, nature needs all the help it can get.

Twice in past houses I've lived in, I've found a yellowjacket nest entry hole beneath the bottommost board of the siding. One was right next to the back door of the house and if closed the door too hard they would come out to defend the nest. I tried one store brand of wasp/hornet killer on them, but it didn't seem to have any effect. The force of the spray would knock them to the ground, but they would shake off, and fly away, seemingly unharmed. I tried a stronger name-brand wasp/hornet spray, that killed the wasps on contact, but those in the nest stopped using the poisined entrance, and found another way out of the nest directly into the basement. Another time I had a yellowjacket nest (which is probably what pennysworth son found) in the ground in our yard 3 feet from the corner of where we would set up the volleyball net. (Bump. Set. Sting. :-) Based on a suggestion from a friend, I ran an extension cord out into the yard and set the shop-vac there, with its snout right next to the hive entrance, sucking up the wasps as they left or came back, for several hours. The next morning when I crept out to check on the nest, I discovered that something had come by in the night, dug open the entrance to the nest, and pulled out and munched on the remaining larva filled nest pieces, leaving a hole 6 inches across and about 2 feet deep.

Oh my, Aloha - 20 nests?! I've wondered if we might get them in our attic, too, as late last summer a piece of our vinyl siding fell off of the roof edge. We haven't put it back on yet as it's all the way to the top and we'll need a really tall ladder to get up there. We may have to hire someone for that job - neither one of us wants to, or should be, on a ladder that tall! I know what you mean, Skybird, about seeing old nests around and yet still see the wasps. Maybe they were their old nests?! I don't know. And I also thought that one fake nest looked like a chinese lantern - it's the same kind of fabric and wire frame. Also, you can't see it in the pic, but it has a hole in the side so it looks like a nest of sorts. But I kinda of wonder if the wasps would just go inside of it and make a nest of their own there! I know they did that in the bird houses I put up along our fence for decoration - I had to plug up the holes so they wouldn't do that any more. So I couldn't resist making my own version of the fake wasp nest, just to see if the concept would work. I recycled/upcycled items I had around the house already to make it - took two 5" peat pots and placed them together at the large end, then slipped a plastic mesh wrap (that they put over the glass bottle of wine I bought at Total Beverage) over them to hold them together, then glued the seam. I spray painted it black, but didn't like the looks of it. So I covered it all with paper mache, I then spray painted it black with a little gray. Now, it's not any prettier than the waspinator, and maybe even a bit uglier, but didn't really cost me anything to make! Maybe this is close enough in shape to fool the foolish wasps - we'll see! If it does, I'll make some more!! Here's my recycled/upcycled wasp nest decoy:

You pay for a caretaker to do periodic maintenance. Not just wasps are an issue when a home sits unoccupied.