division or separation
- Seed may not breed true.
Germination temperature: 70 F to 80 F
Days to emergence: 8 to 12
Seed can be saved 6 years.
Plant root divisions (basal stem pieces with attached roots) after last frost, 2 to 3 feet apart in rows 2.5 to 3 feet apart.
from seed not recommended because results are highly variable and
usually inferior to parent plants. But if you do, start seeds about 8
to 12 weeks before last frost. Harden off in cold frame. Cold treatment
of starts (keeping temperature between 35 F and 50 F for about 10 days)
can induce flowering in first-year plants. Transplant outside after
soil has reached 60 F.
Benefits from the use of a low-nitrogen
fertilizer (high in phosphorus and potassium), which can be
incorporated before planting.
Plants usually don’t flower the first year.
increase chance of overwintering, head back to 12 inches and cover with
leaves, covered with baskets or boxes, and heap more leaves over the
top of the basket. Another alternative is to dig roots and store in a
cold (but not freezing) room. Pot up about a month before transplanting
out after last frost.
While individual plants may live up to 15 years or more, divide about every 3 years to keep planting productive.