We've used Snyder's Weed Control for a few years. They come to spray once a year and it takes care of the weeds. We've only had to call them back once last year when the weeds popped out. They immediately took care of the problem. I'm very pleased with whatever they use and it's application. I'm also pleased with the guarantee. If you have any trouble, they are quick about coming out and taking care of the problem.