Elegant blue blooms for shady borders and woodland gardens
🌿 Plant Overview
- Botanical Name: Corydalis elata ‘Blue Heron’
- Common Name: Blue Heron Corydalis
- Family: Papaveraceae
- Type: Herbaceous perennial
- Hardiness: RHS H7 (down to -20°C or lower)
- Height & Spread: 30–40cm tall × 30cm wide
- Flowers: Intense cobalt-blue tubular flowers
- Foliage: Finely divided, ferny, grey-green leaves
- Scent: Sweetly scented flowers
🌱 Planting
- Best Time to Plant: Spring or autumn
- Soil: Moist, humus-rich, well-drained soil
- Soil Type: Suitable for loam, clay (improved), or sandy soils
- Not Suitable For: Very dry, shallow chalk or free-draining gravel unless heavily improved with organic matter
- pH: Neutral to slightly acidic
- Light Requirements: Partial shade to full shade
- Spacing: Allow 25–30cm between plants
Tip: Corydalis ‘Blue Heron’ prefers consistently moist, cool soils – work in plenty of leaf mould or compost to improve clay or sandy ground.
🌼 Seasonal Interest
- Flowering Time: May to September (with breaks in hot weather)
- Foliage Interest: Deciduous – foliage may disappear in high summer and reappear in autumn
🌦️ Care & Maintenance
Watering
- Keep soil evenly moist, especially during dry spells.
- Avoid waterlogging.
Feeding
- Mulch annually with leaf mould or garden compost in early spring.
- Optional: feed with a balanced liquid fertiliser in late spring if growth is sluggish.
Pruning & Tidying
- Deadhead spent flowers to encourage continued blooming.
- Remove tired foliage in summer if it dies back – fresh leaves may re-sprout later.
Pests & Diseases
- Generally pest-free
- May be affected by slugs or snails in spring – protect young growth
🌸 Design Tips
- Pair with ferns, hostas, Pulmonaria, Brunnera, or Tiarella
- Great for shady borders, woodland gardens, or underplanting shrubs
- Perfect under deciduous trees where spring light is strong and summer shade protects the plant
🪴 Container Growing
- Can be grown in pots with rich, moisture-retentive compost
- Keep shaded and cool in summer
- Water regularly to avoid drying out
✂️ Propagation
- By Division:
- Divide clumps in spring or early autumn when dormant
- Replant immediately at the same depth
- From Seed:
- Can be grown from fresh seed sown as soon as ripe
- Germination can be erratic; best for patient growers!
🔁 Troubleshooting
| Problem | Likely Cause | Solution |
|---|---|---|
| Sudden summer dormancy | Natural reaction to heat/dryness | Water well, leave alone – it may re-emerge |
| Poor flowering | Too much sun or dry soil | Move to more shaded, damper spot |
| Leaves nibbled | Slugs or snails | Use barriers or wildlife-friendly pellets |
🌿 Summary
Corydalis ‘Blue Heron’ is a quietly stunning addition to the shady garden, valued for its long flowering season and ethereal blue flowers. Once settled in the right spot, it can form slowly spreading clumps that return reliably year after year.
