This source reports three treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around September 25, 2026 for a May 3 last frost.
- 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: light
about 6 months from start to sowing. Then 12 days to germinate.
100% germination in 10–12 days.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around June 19, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 18, 2026.
- 1
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
- 3
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 9 months from start to sowing. Germination time not stated; 21 days assumed.
80% germination.
Protocol 3
DerivedN. C. Deno, 1993- 1
Cold moist stratification
Temperature: 40°F 4°C
No stated waiting before sowing.
0% germination.
Nothing germinated at 40.
This source doesn't state how long.