Linda, after I planted Penny royal around my ponds I have not had any fleas or ticks at all for three years now. I am not certain that is the reason but it sure does P.O. my vet to be so irregular buying the expensive flea pills for the dogs.
My issue is fire ants. I do not use chemicals at all here and DE only goes so far. I think this year I just might break down and go nuclear on them. They really ruin my flip flop look