How to grow lavender hedge
Overview
Lavender hedge (Lavandula dentata) is a compact, evergreen shrub grown for its fragrant grey-green foliage and purple flower spikes. It is used to create low, informal hedges that provide structure and texture in sunny, dry gardens. It tolerates heat and poor soil but needs excellent drainage and full sun to thrive.
Varieties
- Lavandula dentata 'Candida' — A compact, white-flowered form with strong fragrance, popular for hedging in Australian gardens.
- Lavandula dentata 'French' — The common grey-green form with purple flowers, widely grown for low hedges in temperate and subtropical zones.
Soil Preparation
Lavender hedge prefers slightly alkaline soil (pH 6.5–7.5) with excellent drainage. Add lime if soil is acidic. Incorporate coarse sand or gravel into heavy clay. Avoid rich organic matter, which can cause leggy growth and rot.
Growing Guide
Plant lavender hedge in a position with full sun and well-drained soil; raised beds or mounds improve drainage. Space plants 30–45 cm apart for a dense hedge. Dig in coarse sand or gravel if soil is clay. Water deeply but infrequently after establishment, allowing the soil to dry between waterings. Avoid overhead watering to reduce fungal risk. Mulch with gravel or pebbles, not organic matter, to keep the crown dry.
Care
Feed with a balanced slow-release fertiliser in early spring. Prune lightly after flowering, cutting back to just above new growth. Remove spent flower stems and any dead wood in late autumn. Do not prune into old wood.
Companion Planting
Lavender hedge pairs well with roses, especially old-fashioned or shrub types, as its scent repels aphids. It also suits salvias, rosemary, and other Mediterranean herbs. Avoid planting near moisture-loving plants like ferns or impatiens, which can cause root rot.
Common Pests & Risks
Root rot and fungal diseases (e.g., Phytophthora) occur in poorly drained or overwatered soil. Whitefly and spittlebugs may appear in humid conditions; control with a strong water spray or insecticidal soap. Avoid overhead watering and ensure good air circulation.
Harvesting
Harvest lavender flowers when the first buds on a spike open, cutting long stems in the morning after dew dries. For dried flowers, hang bunches upside down in a dark, airy space. Fresh flowers can be used in sachets or culinary dishes.
Troubleshooting
Yellow leaves: overwatering or poor drainage — reduce water and improve soil. Brown leaf tips: salt buildup or dry air — flush soil with water. Leggy growth: too much shade or nitrogen — move to full sun and reduce fertiliser. Wilting: root rot — remove plant and improve drainage. No flowers: insufficient sun or over-pruning — ensure full sun and prune after flowering only.