How to grow lemon myrtle
Overview
Lemon myrtle (Backhousia citriodora) is an Australian rainforest shrub from the Myrtaceae family, prized for its intensely lemon-scented leaves. It is grown both as an ornamental and for its edible foliage, which is used in teas, seasonings, and cooking. Key to success is providing consistent moisture and protection from harsh frost while establishing.
Varieties
- Backhousia citriodora 'Lemon Queen' — A compact selection with denser foliage, ideal for smaller gardens and hedging.
- Backhousia citriodora 'Dwarf' — Grows to 1.5 m, suited to pots and tight spaces, with the same intense lemon scent.
Soil Preparation
Lemon myrtle prefers slightly acidic soil (pH 5.5–6.5) with good drainage. Before planting, incorporate well-rotted compost or aged manure and a handful of native-friendly fertiliser. Avoid heavy clay; if present, raise the bed or add gypsum and coarse sand to improve drainage.
Growing Guide
Plant lemon myrtle in a position with bright, filtered light or morning sun, avoiding harsh afternoon rays. Space plants 2–3 m apart to allow for their natural bushy spread. Dig a hole twice the width of the root ball and amend with well-rotted organic matter. Water deeply at planting and maintain even moisture through the first year. In cooler zones, plant against a north-facing wall for extra warmth.
Sowing
Seeds are very fine and slow to germinate (4–8 weeks). Sow on the surface of a seed-raising mix, keep moist and warm (20–25°C), and do not cover. Transplant seedlings at 10–15 cm tall into individual pots. Direct sowing is not recommended due to low germination rates.
Care
Feed in early spring with a slow-release native fertiliser low in phosphorus. Lightly prune after harvest to promote branching and remove any dead or crossing stems. Mulch with organic matter to 5–8 cm depth, keeping it clear of the trunk to prevent rot.
Companion Planting
Grow lemon myrtle alongside other native shrubs like lilly pilly (Syzygium smithii) and native mint (Mentha australis) for a cohesive habitat. Avoid planting near eucalypts or grevilleas, which may host myrtle rust. Keep away from heavy feeders like citrus that compete for nutrients.
Common Pests & Risks
Scale insects and psyllids can cause leaf distortion and sticky honeydew; treat with horticultural oil or neem spray. Myrtle rust (Austropuccinia psidii) appears as bright yellow-orange pustules on new growth; prune affected parts and apply a registered fungicide. Monitor for leafminer in humid conditions.
Harvesting
Harvest mature leaves from the outer canopy once the plant is at least 1 m tall, typically from late spring through autumn. Snip individual leaves or small branches, and use fresh or dry in a cool, dark place. Regular picking encourages bushier growth and maintains shape.
In the Kitchen
Use fresh or dried leaves in teas, marinades, and desserts for a strong lemon flavour. Store dried leaves in an airtight jar away from light for up to 6 months. Infuse leaves in hot water or oil for a few minutes before straining.
Troubleshooting
Yellow leaves: caused by overwatering or poor drainage; reduce watering and improve soil. Brown leaf edges: from dry air or salt build-up; mist regularly and flush soil. Stunted growth: due to cold or lack of nutrients; protect from frost and feed in spring. Leaf drop: from sudden temperature change; site in a sheltered spot. Myrtle rust: bright orange pustules on new growth; prune and treat with fungicide.