I'm a plant fanatic / veterinarian also. This article is so useful to me and my clients. I'll be sharing this great article with my clients and friends. FWIW and this is just my observations from North Alabama. The most effective and safest product on the market now is the Spinosad "Comfortis". Frontline is not worth the plastic it is sold in. It used to be a wonderful product (10 years ago) but unfortunately fleas have developed resistance to this product.