Helianthemum nummularium
Rock Rose · Common Rock Rose · Common Rock-Rose
About the plant
What it is and where it grows — not part of any germination protocol.
The plant
- Habit
- Herbaceous perennialPlant Finder
- Height
- 0.5-1 ftPlant Finder
- Spread
- 2-3 ftPlant Finder
- Flower
- Showy; pastel pink or yellowPlant Finder
- Blooms
- May to JunePlant Finder
- Native range
- Albania, Algeria, Austria, Baleares, Baltic States, Belarus and elsewhereGBIF Backbone Taxonomy
- Native range
- Western Asia, EuropePlant Finder
- Hardiness zones
- 5-7Plant Finder
Growing conditions
- Sun
- Full sun
- Watering
- Dry
Toxicity is noted only where a source states it. No note here is not a finding of safety.
Sources: Plant Finder — Missouri Botanical Garden; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.
This source reports two treatments. Both are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty High
Start around March 22, 2027 for a May 3 last frost.
Cold moist stratification
Temperature: 40°F 4°C
Three seeds of fifteen, in the 2nd week.
No stated waiting before sowing. Then 14 days to germinate.
20% germination in 14 days.
Three times the warm sowing, and it happens in the cold.
This source doesn't state how long.
Protocol 2
DerivedN. C. Deno, 1993Start around March 20, 2027 for a May 3 last frost.
Warm moist stratification
Temperature: 70°F 21°C
One seed of fifteen, on the 16th day.
Cold moist stratification
Temperature: 40°F 4°C
Warm moist stratification
Temperature: 70°F 21°C
No stated waiting before sowing. Then 16 days to germinate.
7% germination in 16 days.
This source doesn't state how long.