Polemonium chartaceum
Genus Polemonium
This source reports two treatments. Both are shown.
Protocol 1
DerivedN. C. Deno, 1998Difficulty High Rated by us, not by the source.
Start around August 13, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 12, 2026.
- 1
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
about 6 months from start to sowing. Then 56 days to germinate.
27% germination in 56 days.
Protocol 2
DerivedN. C. Deno, 1998Difficulty Very high Rated by us, not by the source.
Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.
- 1
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 2
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
about 6 months from start to sowing. Germination time not stated; 21 days assumed.
3% germination.