Perennial. Hardy in zones 4-8.
Long-lived and dependable. Zones 4-8. Start seed 10-12 weeks before last frost date. Press seed onto surface of potting mix; do not cover with soil. Germinate at an optimum temperature of 18- 21ºC, if no germination within 4 weeks then pre-chill seed for 2-3 weeks. When a manageable size, plant into a sunny garden 18 inches apart. Clumps may be divided after 3-4 years in spring. Blooms July to October.