Seed Type: Perennial | USDA Zones: 4–9 | Height: 18–36 in (45–90 cm)
Bloom Time: Late summer | Sun: Full sun to part shade
Attracts: Pollinators | Deer resistant
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.
COLD STRATIFICATION:
- Mix seeds with a small amount of moist sand or vermiculite.
- Place in a sealed plastic bag.
- Refrigerate for 2–4 weeks at 35–40°F (2–4°C).
Important: If seedlings emerge in the bag, plant them immediately in pots or trays.
When to Sow
How to Sow Indoors
- Start 6–8 weeks before your last expected frost.
- Fill seed trays or pots with a well-draining, sterile seed-starting mix.
- Lightly press seeds onto the surface—do not cover them. These seeds require light to germinate.
How to Sow Outdoors (Fall or Winter)
- Outdoors (for natural stratification): Sow in late fall. The cold, moist conditions of winter will naturally stratify the seeds and improve spring germination.
- Choose a well-drained, sunny location.
- Lightly rake the soil surface to loosen it.
- Scatter seeds thinly over the surface—do not bury them. These seeds need light to germinate.
- Gently press seeds into the soil using your hand or a flat board to ensure good contact.
- Do not cover with soil. If desired, you can sprinkle a very thin layer of fine sand or vermiculite to help keep them in place without blocking light.
- Water gently and allow nature to provide cold, moist conditions over winter.
Germination Conditions
- Optimum Temperature: 68–75°F (20–24°C)
- Germination Time: ⏳ 14–28 days AFTER stratification
- Light: Needs light to germinate – do not cover deeply. Press seeds lightly onto soil.
- Use grow lights to maintain 12–16 hours of light per day.
- Medium: Use a well-draining seed-starting mix. Keep soil 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.
After Germination
- Provide plenty of light – a sunny windowsill or grow lights work well.
- Once seedlings develop 2–3 sets of true leaves, transplant into individual pots.
- Harden off before moving outdoors.
Transplanting Outdoors
- Choose a spot with full sun and well-draining soil.
- Space 12–18 in (30–45 cm) apart.
- Water moderately. Once established, plants are drought-tolerant.
Care Tips
- Prune in late fall or early spring to maintain shape.
- Can spread via rhizomes – divide clumps as needed.
- Excellent for naturalistic gardens and dry landscapes.