Photo 12 of 18Gayfeather. The dramatic spires of this sun-loving perennial create an eye-catching vertical element in the late summer garden. Reaching up to 4 feet tall, the lavender, purple, pink or white blooms attract butterflies and hummingbirds. Gayfeather needs full sun and air circulation to avoid mildew; plant corms 8 to 10 inches apart. Can also be planted in fall. USDA Hardiness Zones: 3 to 9; needs winter mulch in Zones 3 and 4.