YJ Update

We have sprayed the yellowjackets' nest four times now. They appear unaffected. You have to go out after dusk and hit 'em when they are settled down for the night. Last night, I admit at my suggestion, my husband stuffed the holes in the compost bin and the gaping hole at the end of our landscape log next to the bin with Great Stuff* after shooting in more poison, hoping to seal them inside to die. They were out as usual this morning, obviously entering and leaving their hideout through other, more clandestine means.
The icing on the foolhardy cake was witnessed this morning as my not to be defeated husband took our garden hose and aimed it at the nest - in broad daylight! I watched from the upstairs window, aghast, as he sent streams of cold water onto the compost bin and surrounding area, occasionally jumping back, jogging left and right and flipping the spray up and down, side to side as individual insects obviously zipped by. He looked like Luke Skywalker battling an invisible enemy. It was quite a scene. Now everything I've heard and read intimates that this is not a good idea. I went to find the first aid kit, but he returned to the house a minute later, unscathed. Lucky man.

(*Great Stuff comes in a can and is used to plug up holes in your foundation or whatever you need plugged up. It is commonly used to seal cracks in a house to make it weathertight. You spray the yellowish foam into the space and it immediately expands, usually bulging out of the space, and then hardens later. You return then and scrape off the excess stuff.)