Seed Treatment
- Cold Stratification:
- Mix seeds with moist sand or peat moss in a plastic bag.
- Store in the refrigerator at 35–40°F (1–4°C) for 4–6 weeks.
- Check regularly to ensure moisture but avoid mold growth.
- Scarification:
- Lightly rub seeds with fine sandpaper or soak in warm water for 12 hours before sowing.
Planting Instructions
- Sowing Time:
- Best sown in late autumn or early spring after stratification.
- Direct sow outdoors in fall for natural stratification.
- Soil Preparation:
- Prefers well-draining, sandy, or loamy soil.
- Soil pH: 6.0–7.5 (neutral to slightly acidic or alkaline).
- Avoid heavy, waterlogged soils.
- Sowing Depth & Spacing:
- Sow seeds ⅛ inch (3 mm) deep on the soil surface and lightly press them down.
- Space seedlings 12–18 inches (30–45 cm) apart.
- Temperature & Light Requirements:
- Germination temperature: 65–75°F (18–24°C).
- Requires full sun for best growth and flowering.
- Watering:
- Keep soil moist but not soggy until germination.
- Once established, Eryngium is drought-tolerant and requires minimal watering.
- Germination Time:
- Seeds take 3–5 weeks to germinate after cold stratification.
- Some seeds may take several months if conditions are not ideal.
- Transplanting:
- When seedlings develop 2–3 sets of true leaves, transplant them carefully.
- Avoid disturbing the deep taproot, as Eryngium does not transplant well once mature.
- Care After Planting:
- Requires little maintenance once established.
- Apply mulch around plants to suppress weeds and retain moisture.
- Avoid excessive fertilization, as it thrives in nutrient-poor soil.
- Deadhead spent flowers to encourage more blooms or leave them for ornamental winter interest.
Additional Tip:
Eryngium planum is deer-resistant, attracts pollinators, and makes an excellent cut or dried flower for floral arrangements!