Brake cleaner... That shit will kill anything. I can't speak for plants, but I found a huge ant colony beside my porch today. I usually spray Mr. Clean or whatever household stuff I have around on them and it does a good job, but today I had another idea. I saw the can of brake cleaner and decided to see what happens. Not only did the brake cleaner kill all the ants instantly on contact, it completely liquified them. I went around the perimeter of my porch and now there are ZERO ants anywhere. Don't get me wrong, I don't think it's a great idea to spray brake cleaner on the ground, but it worked for me and if they come back, forget the Raid, I'm headed to Auto Zone.