Chrysanthemums contain chemical compounds that act as natural insecticides, which are processed and sold as pyrethrum. It’s a go-to natural pesticide for dealing with fleas, ants, ticks, silverfish and bedbugs. Certain types of mums do a better job at repelling insects than others. The ones used commercially for extracting pyrethrums include painted daisy (Chrysanthemum coccineum) and Dalmatian daisy (Chrysanthemum cinerariifolium). Use these perennial mums in the garden to add daisy-like flowers to planting designs.