for a couple years and now I have just the occasional one that jumps over from my neighbors property. I have read that others have had mixed success with this method but I had great results with a really big "air potato" problem. I think the key is to keep after it regularly for a couple years. Now I only have to spot spray or dig it up right away if I spy one of those devilish things! Mine were not in the lawn which would present a different problem altogether but for other areas, this did the trick!