7. Fennel (Foeniculum vulgare) Long-lasting fennel flowers are extremely attractive to all nectar-feeding beneficial insects, and the feathery green or purple foliage looks wonderful in spring and early summer. Fennel is a host plant for the caterpillars of the anise swallowtail butterfly. The seeds and leaves are also eaten by humans, and are excellent in salads (leaves) or spaghetti sauce (seeds). The plants grow about 5 feet high and are perennial in zones 6-9.
Photo: (cc) Weisserstier/Flickr