Height: 20 inches Width: 16 inches  Sun: Full sun. Soil Moisture: Moist, well-drained. Hardiness: Zones 8 to 10 Culture: Grows best in moist, but well drained, pH-neutral soil. Pot or plant in garden with crown level with soil. Deadhead and remove spent flower stems regularly after flowering. Cut back by at least half of last year's growth in spring. Water early in the day as needed during growing season, to allow foliage to dry.