About the plant
What it is and where it grows — not part of any germination protocol.
The plant
- Habit
- Herbaceous perennialPlant Finder
- Habit
- Biennial, Forb/herbPLANTS Database
- Height
- 2-4 ftPlant Finder
- Spread
- 2-3 ftPlant Finder
- Flower
- Showy, fragrant; white to lavenderPlant Finder
- Blooms
- June to AugustPlant Finder
- Native range
- Europe to Central AsiaPlant Finder
- Hardiness zones
- 5-9Plant Finder
- Note
- Deno tested a 60 cm and a 180 cm form separately; only the tall one germinates cold.Seed Germination Theory and Practice, 2nd ed.
- Note
- Fragrant leaves. Tolerates deer, drought and shallow rocky soil.Plant Finder
Growing conditions
- Sun
- Full sun
- Soil
- Average, medium moisture, well-drained
- Watering
- Medium
Toxicity is noted only where a source states it. No note here is not a finding of safety.
Sources: Plant Finder — Missouri Botanical Garden; PLANTS Database — USDA NRCS; Seed Germination Theory and Practice, 2nd ed. — N. C. Deno.
This source reports 8 treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1993Difficulty Low Rated by us, not by the source.
Start around March 30, 2027 for a May 3 last frost.
- 1
Sow on the surface — do not cover
Temperature: 70°F 21°C · Light: light
No stated waiting before sowing. Then 6 days to germinate.
61% germination in 2–6 days.
The best of eight. Deno's 180 cm form.
Protocol 2
DerivedN. C. Deno, 1993Difficulty Low Rated by us, not by the source.
Start around March 24, 2027 for a May 3 last frost.
- 1
Sow on the surface — do not cover
Temperature: 70°F 21°C · Light: light
No stated waiting before sowing. Then 12 days to germinate.
46% germination in 2–12 days.
Light is worth fifteen points on this form. Deno's 60 cm form.
Protocol 3
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 29, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: dark
No stated waiting before sowing. Then 7 days to germinate.
43% germination in 2–7 days.
Dark costs the tall form eighteen points. Deno's 180 cm form.
Protocol 4
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around January 11, 2027 for a May 3 last frost.
- 1
Cold moist stratification
Temperature: 40°F 4°C
41%, over 7-12 weeks.
- 2
Warm moist stratification
Temperature: 70°F 21°C
No stated waiting before sowing. Then 84 days to germinate.
41% germination in 49–84 days.
The tall form germinates cold; the short form barely does at all. Deno's 180 cm form.
This source doesn't state how long.
Protocol 5
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Sow outdoors and leave it
No stated waiting before sowing. Germination time not stated; 21 days assumed.
40% germination.
40% outdoors. Deno's 60 cm form.
This source doesn't state how long.
Protocol 6
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 24, 2027 for a May 3 last frost.
- 1
Sow and cover
Temperature: 70°F 21°C · Light: dark
No stated waiting before sowing. Then 12 days to germinate.
31% germination in 2–12 days.
Dark costs the short form fifteen points. Deno's 60 cm form.
Protocol 7
DerivedN. C. Deno, 1993Difficulty Moderate Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Sow outdoors and leave it
No stated waiting before sowing. Germination time not stated; 21 days assumed.
27% germination.
27% outdoors, against 40% for the short form. Deno's 180 cm form.
This source doesn't state how long.
Protocol 8
DerivedN. C. Deno, 1993Difficulty Very high Rated by us, not by the source.
Start around March 15, 2027 for a May 3 last frost.
- 1
Cold moist stratification
Temperature: 40°F 4°C
1% here.
- 2
Warm moist stratification
Temperature: 70°F 21°C
A further 2%.
No stated waiting before sowing. Germination time not stated; 21 days assumed.
2% germination.
1% in the cold and 2% after it. The short form will not take a cold start. Deno's 60 cm form.
This source doesn't state how long.