I read online that leafcutter ants will eat dry grits, and it swells up and they die. Even though they supposedly will eat only fungus, i thought i would try after they ate EVERY leaf off my gardena cuttings. It takes 48 hours and today is the 24 hour mark. They are busily picking up grits and carrying it back to their nests. They have stopped eating my plants!!! Hey, im willing to buy thęm grits, even if it doesnt kill them, if they will leave my plants alone. Adding grits to shopping list.

Update on leafcutter ants after applying grits. I dont have even one leafcutter ant in last years veggie garden. They had been eatting all my onions. Looked like a mower went thru there. I have a new nest outside this years garden, and happily chewing in my wildflower garden. So ive put out a few more piles.

Interesting. Let us know if this year's efforts work.

I wish I could find a picture that's not copyrighted so I could show all of you leaf cutter ants in action. They are amazing if you don't garden. Sort of like deer and bunnies are so cute. Anyway, they are driving me crazy this year. Started on my onions the day I put them out.
Cornmeal not working.
Grits not working
Surround spray clogged the sprayer and won't stick to plants. I now apply dry with a sitter and ants go away.
Covering plants with frost cloth and pinning it down helps.
I say helps because they left my onions and ate my strawberries. Did everything above for strawberries.
Then, they moved to my cabbage. Ditto above
Then, they ate my pollinator wild flowers.
Then they ate my potato leaves
Today, they were eating my violets.

Wow! You really do have a problem. Here they like the peach trees, the china berry trees (they can have them), and the roses - and not all of those. Yours seem more omnivorous! I defended the peach trees by tying rags soaked in bug spray around the trunks. Sprinkling leaf cutter ant bait along their trails also helps - I think. Good luck!