For optimal germination rates, initiate seed propagation indoors under controlled conditions—unless the species exhibits a high sensitivity to root disturbance. This approach allows precise regulation of temperature, humidity, and light, improving germination consistency and seedling viability. Do not skip any recommended seed treatments, as they are essential for uniform and successful germination.
Seed Treatment
Cold Stratification: 4–6 weeks at ~4°C / 39°F
➤ Mix seeds with a small amount of damp sand.
➤ Place in a sealed plastic bag and refrigerate at 35–40°F (2–5°C).
➤ Check weekly. If seedlings emerge early, remove them from the bag and plant immediately.
Best Time to Sow:
Indoors:
- Start 8–10 weeks before your last expected frost (typically late winter to early spring, e.g., February to March in temperate zones).
- Sow in trays or pots, cover lightly, and place in a cool location for cold stratification (4–6 weeks at ~4°C / 39°F), then move to warmth (~65–70°F or 18–21°C) for germination.
Outdoors:
- Fall sowing (September–November) is ideal. Seeds will naturally cold stratify over winter and germinate in spring.
- Alternatively, sow in early spring, as soon as the soil is workable
Germination Time
Up to 60 days AFTER stratification
Optimum Germination Temperature
65–70°F (18–21°C)
How to Sow
➤ Sow seeds on the surface of moist, well-draining seed-starting mix.
➤ Do not cover—light aids germination.
➤ Use grow lights to maintain 12–16 hours of light per day.
➤ Keep consistently moist but not soggy.
Humidity: Use a humidity dome or clear cover to maintain consistent moisture during germination. Open the dome BRIEFLY once per day to allow fresh air in and reduce mold risk. Remove the dome entirely once seedlings emerge.
Planting Location
➤ Best in partial shade to dappled sun.
➤ Prefers cool, moist conditions and rich, well-drained soil.
? Post Germination Care
➤ Once seedlings have 2–3 true leaves, transplant carefully into individual pots.
➤ Harden off before moving outdoors.
➤ Space plants 12–18 inches apart in the garden.
➤ Water regularly but avoid waterlogging.
Additional Tips
✔ Perennial in USDA Zones 3–9
✔ Attractive to hummingbirds & pollinators
✔ Great for borders, woodland gardens, or shaded containers