How to grow valerian
Overview
Valerian is a herbaceous perennial grown for its tall stems of pinkish flowers and its strongly scented roots, used in herbal teas and sleep aids. It thrives in full sun and moist, well-drained soil, and is valued for filling gaps in garden beds with quick, lush growth.
Varieties
- Valeriana officinalis — The standard species, widely available in Australian nurseries, with tall pink flowers and strong root scent.
Soil Preparation
Valerian prefers a neutral to slightly alkaline pH (6.5–7.5) and rich, loamy soil with good drainage. Incorporate well-rotted compost or aged manure before planting; avoid heavy clay or waterlogged spots.
Growing Guide
Plant valerian in full sun with rich, loamy soil that stays consistently moist but never waterlogged. Space seedlings 30–40 cm apart; direct sow or transplant after frost. Mulch heavily to retain moisture and suppress weeds. Cut back flower stems after bloom to encourage a second flush and keep plants compact.
Sowing
Sow valerian seeds 5 mm deep in seed trays or direct in the garden after the last frost. Germination takes 10–14 days at 15–20°C. Thin seedlings to 30 cm apart; transplant when 10 cm tall.
Care
Feed with a balanced organic fertiliser in early spring and again after flowering. Cut back spent flower stems to encourage a second flush. Divide clumps every 3–4 years to maintain vigour and prevent overcrowding.
Companion Planting
Valerian attracts earthworms and beneficial insects, making it a good companion for vegetables like brassicas and carrots. Avoid planting near strong-scented herbs like sage or rosemary, which may compete for root space.
Common Pests & Risks
Aphids can cluster on new growth; spray with a strong jet of water or use insecticidal soap. Slugs and snails may damage young leaves in wet weather; control with beer traps or crushed eggshells.
Harvesting
Harvest valerian roots in autumn of the second year after planting, when the plant has died back and the roots are plump and aromatic. Dig carefully, wash, and dry in a warm, dark place for storage.
Troubleshooting
Yellow leaves: overwatering or poor drainage; reduce watering and improve soil. Brown edges: underwatering or hot sun; increase water and provide afternoon shade. Stunted growth: root-bound or poor soil; divide and replant in rich compost. Powdery mildew: humid air; space plants and avoid overhead watering.