9. Pussy Willows (Salix species) Willows are especially valuable because they produce pollen so early in the spring, when many beneficials are just emerging. Pussy willows are super-easy to grow and fun to cut for flower arrangements. Most garden centers will carry pussy willows in spring, or you can root cuttings from a neighbors' shrub in water.
Photo: (cc) Dag Endresen/Flickr