Flowers not only draw pollinators to the yard, but some of them also deter pests. French marigolds are great for warding off destructive nematodes and whiteflies. Chrysanthemums actually contain their own insecticide (pyrethrin),so they're great for repelling fleas, ticks, flies, and other insects. Cosmos are known for fending off the corn earworm. I don't use insecticides, so I thought I'd share what has worked for me over the years. Do you have any to add? I'd love to hear about it.