Hydrangea arborescens
Genus Hydrangea
This source reports 5 treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1996Difficulty Low Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: light
No stated waiting before sowing. Then 21 days to germinate.
100% germination in 7–21 days.
Protocol 2
DerivedN. C. Deno, 1996Difficulty Moderate 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: light
about 6 months from start to sowing. Then 21 days to germinate.
100% germination in 21 days.
Protocol 3
DerivedN. C. Deno, 1996Difficulty Low Rated by us, not by the source.
Start around March 22, 2027 for a May 3 last frost.
- 1
- 2
Sow and cover
Temperature: 70°F 21°C
No stated waiting before sowing. Then 14 days to germinate.
100% germination in 14 days.
Protocol 4
DerivedN. C. Deno, 1996Difficulty 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. Then 21 days to germinate.
12% germination in 21 days.
Protocol 5
DerivedN. C. Deno, 1996Difficulty Very high Rated by us, not by the source.
- 1
Sow outdoors and leave it
Up in May.
No stated waiting before sowing.
2% germination.
This source doesn't state how long.