This source reports two treatments. Both are shown.
Protocol 1
DerivedSER, INSR and RBG Kew, 2026Difficulty Low Rated by us, not by the source.
Start around November 16, 2026 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 70 days · Temperature: 50°F 10°C · Light: either · Medium: 1% agar
12 hours light, 12 dark.
about 2 months from start to sowing. Then 70 days to germinate.
100% germination in 70 days.
It germinates in the cold rather than after it. SID holds 20 such records.
Protocol 2
DerivedSER, INSR and RBG Kew, 2026Difficulty Low Rated by us, not by the source.
Start around March 8, 2027 for a May 3 last frost.
- 1
Cold moist stratification
Duration: 14 days · Temperature: 59°F 15°C · Light: either · Medium: 1% agar
8 hours light, 16 dark.
14 days from start to sowing. Then 14 days to germinate.
100% germination in 14 days.