This source reports two treatments. Both are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 21, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 20, 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
- 3
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 4
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
about 12 months from start to sowing. Then 21 days to germinate.
80% germination in 3–21 days.
Protocol 2
DerivedN. C. Deno, 1993Difficulty High Rated by us, not by the source.
Start around January 24, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on January 23, 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
- 3
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
- 4
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
about 12 months from start to sowing. Then 77 days to germinate.
30% germination in 63–77 days.