6. Golden Marguerite (Anthemis tinctoria) This long-blooming perennial produces bright yellow 2 inch daisies that are highly attractive to five key kinds of beneficials—ladybugs, lacewings, flower flies, tachinid flies and mini-wasps. It was the only plant out of 170 species to score this well in a 3-year study at botanical gardens in Colorado and Wyoming. Golden marguerite thrives in poor soils, growing 2 to 3 feet high and wide. Deadhead (remove spent flowers) to promote rebloom, and divide plants every 2 to 3 years. Hardy in zones 3 to 7.
Photo: (cc) Sabrina Huber/Flickr