Ground-nesting Yellowjacket Wasps

While my 16yo son was mowing the lawn with our push-reel mower, our neighbor on one side slowed down his rider-mower to a crawl, grinned at my son, and said, “That’s some ancient technology you have there, boy.” I bought the reel mower thinking it would provide me with some exercise, and it’s quiet enough that I can listen to an audiobook while doing the lawn. As it turns out, my son, who at 16 has no interest in social media. and who voluntarily turns off the computer after his one- or two-hours of daily “screen time,” rather enjoys using the rotary analog mower. Or at least he did until the other day, when he came in saying he had mowed over a wasp nest in the ground, and was stung twice. I found not one, but two nests.

From what I’ve learned about ground-nesting wasps, I assume these are two different nests, rather than two entrances to the same nest. I guess I’ll find out tonight, when they’re settled in for the night. I’m thinking of putting a glass bowl over one hole (just in case I’m wrong and one hole is an escape tunnel) and trying to flush out the nest with the hose. I gather that water alone won’t do the trick, since surely wasps know how to deal with water coming into that hole; but boiling water? Dish detergent down the hole first, followed by boiling water? Expanding foam insulation? With a colander or screen or something over the hole, so the wasps can’t come out and get me?