Fire ants just chillin by the tree

Hey everyone,

I have a problem. No, it's not substance abuse, it's smaller than that. Much smaller. But at the same time, it's a HUGE pain in the butt (or wherever these things bite you).
Wha'choo talkin' bout, Willis?
I'm talkin bout fire ants, son!

I've been looking at different ways to get rid of them and I think the way I want to go is the cheapest way I've found: Boiling water with a pinch of dish soap( I'll use my Hawaiian Breeze scented one so they can feel like they died in paradise. I'm not a total monster). The only problem I'm seeing online is that boiling water kills the plants that it comes in contact with. I don't care about the grass that's going to be affected, but I'm worried about the tree that these little turds have used as a home.

The mound is pretty big and at the base of a tree that's about 30 years old. Will the boiling water hurt the tree at all? I don't think it will since it's as old and as established as it is, but I just want some input from others before I give those ants a nightmare vacation.

I've attached a picture so you can see the base of the tree plus the mound. It's pretty hard to tell where the mound is since I haven't gotten the weedeater out yet to take care of the grass.

Thanks in advance!

Drenching with plain water can discourage them enough to move elsewhere. Just keep bugging them and eventually they will leave, in my experience. If I'm lucky, once they move to a remote location they get eaten by an armadillo.

Some people say you can kill them by sprinkling cornmeal on the nest, but I have not tried it. Other people say soda water. Either way it means having to buy something to kill ants, which I'm not going to do.