I just did a proposal for a lawn renovation on Keyser Rd in Westport,Ct. I plan to use a product called Tenacity.It’s a great product if you have to seed in the spring.It is applied just before seeding -so new grass can flourish without weeds. Here is an interesting story on how this product came about.A scientist in California noticed that no weeds were growing under a bottle bush(Callistemon citrinus)The scientist came to the conclusion that the plant must be producing allelochemicals that naturally suppress weed competition. The allelochicals were synthesized to produce mesotrine. The active ingredient in Tenacity.