ORGHPS Germination Guide: Sow immediately, Either the viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience. Expose to fluctuation outdoor winter temperatures including freezing for 3 months. Gradually increase light and temperature in the spring. * start in soilless peat-based mix; dry storage > 6 months is fatal, will germinate in second spring

Source: Ontario Rock Garden & Hardy Plant Society