Whether you already have a large flower garden or are looking to start one this spring, here are 7 of the best flowers for butterflies. Before making your picks, be sure to check out which hardiness zone each plant thrives best in. Not sure what zone you’re in? Look up your USDA Hardiness Zone here. Hardiness Zones: 3-8 Hardiness Zones: 3-9 Butterfly bush grows best in fertile, well-drained soil and full sun. To keep the vibrant flowers (and beautiful butterflies!) coming back, be sure to deadhead spent blooms. Hardiness Zones: 5-10 Pro tip: According to the plant pros at Costa Farms, darker blooms and those that are just about to open smell the strongest. Hardiness Zones: 5-9 Hardiness Zones: 3-9 (thrive in 5-8) Hardiness Zones: 3-9