Penstemon duchesnensis
Genus Penstemon
FlowerAndrey Zharkikh from Salt Lake City, USACC BY 2.0This source reports three treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1996Difficulty High Rated by us, not by the source.
Start around November 17, 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: dark
2/13 germinated in this phase.
Steps after step 1 run on after germination.
about 3 months from start to sowing. Then 49 days to germinate.
23% germination in 49 days.
Protocol 2
DerivedN. C. Deno, 1996Difficulty 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
Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
1/14 germinated in this phase.
- 2
Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
about 6 months from start to sowing. Germination time not stated; 21 days assumed.
8% germination.
Protocol 3
DerivedN. C. Deno, 1996- 1
Sow and cover
Temperature: 70°F 21°C · Light: dark
No stated waiting before sowing.
0% germination.
Nothing germinated at 70.
How each step is done, in Deno’s words, and what Verified and Derived mean.
