Backhousia citriodora

Lemon Myrtle

Botanical Name: Backhousia citriodora
Family: Myrtaceae
Origin: Queensland, Australia (subtropical rainforest)
Plant Type: Evergreen small tree; can be maintained as a large shrub with regular pruning

Overview

Backhousia citriodora — Lemon Myrtle — is one of Australia's most celebrated native trees, famed for foliage so richly charged with citral that it out-lemons lemon itself. Native to the subtropical rainforests of south-east Queensland, it adapts beautifully to Adelaide's temperate climate as a graceful feature tree, tall privacy screen, or dense fragrant hedge. Glossy evergreen leaves, a generous flush of fluffy cream-white flowers each summer, and year-round culinary versatility make it one of the most rewarding natives you can plant in a South Australian garden.

Key Features

• Mature Size: 5–8 m H x 4–5 m W (can be maintained at 2–3 m H with regular pruning)
• Growth Rate: Moderate to fast; 40–60 cm per year; upright with a dense, rounded to oval crown that fills in well without staking
• Foliage: Evergreen; glossy, bright to mid-green oval leaves with prominent veining; intensely lemon-scented when crushed — citral content exceeds that of lemon fruit itself
• Flowers: Fluffy, creamy-white flower clusters in dense terminal sprays; summer (November–February); lightly sweet-lemon fragrant; outstanding for pollinators and cut arrangements
• Seasonal Interest: Year-round glossy foliage; peak flowering November–February; persistent floral display extends into early autumn; fresh lemon scent released whenever leaves are brushed
• Wildlife Value: Strongly attracts native bees, honeybees, butterflies, and nectar-feeding birds including honeyeaters and lorikeets; leaves are a food plant for specialist native insects
• Tolerance: Drought-tolerant once established; light frost to –2°C; coastal in sheltered positions; moderate wind; heat-tolerant in part shade
• Planting Density: Tight screening hedge: 80–100 cm apart (1.3 plants per metre); standard informal hedge or privacy screen: 1.2–1.5 m apart (0.8 plants per metre); feature tree: 3–4 m from neighbouring plants
• Pet Friendly: Non-toxic to cats and dogs; leaves are an edible culinary herb for humans; large quantities of any plant material may cause mild digestive upset in pets — discourage excessive grazing

Where It Works Best

• Sunlight: Full sun to part shade; best fragrance and flowering in full sun; tolerates 3–4 hours of direct sun per day in part-shade positions
• Soil: Prefers well-drained loam or sandy loam enriched with organic matter; tolerates clay if drainage is improved with gypsum and compost; mulch thickly to retain moisture and keep roots cool in Adelaide summers
• Water Needs: Establishment (first 12 months): water 2–3 times per week during warm or dry periods; reduce to once weekly in cooler months. Established: summer — deep water once weekly; winter — once every 2–3 weeks or rely on Adelaide's winter rainfall
• Maintenance: Low to moderate; tip-prune after flowering to maintain shape and density; tolerates hard pruning for rejuvenation; harvest foliage year-round for culinary use; apply slow-release native fertiliser in spring
• Lifespan: 50+ years
• Climate Zones: Suited to Adelaide's coastal suburbs, inner metropolitan areas, and sheltered Adelaide Hills positions; performs well across temperate and Mediterranean zones from Victor Harbor to the Barossa; marginal in exposed high-Hills sites with severe frosts (below –3°C) and in the Riverland without supplemental summer irrigation
• Soil pH: Slightly acid to neutral (pH 5.5–7.0); avoid highly alkaline or waterlogged soils

Landscape & Design Ideas

• Plant as a tall aromatic privacy screen along fences or property boundaries — responds vigorously to pruning and can be maintained as a formal to semi-formal hedge at 2–3 m, providing year-round green density
• Use as a courtyard or entertaining-area feature tree where foliage can be casually brushed to release its signature lemon fragrance on warm evenings
• Incorporate into a bush-food or edible garden — harvest fresh leaves year-round as a citrus substitute in cooking, teas, cocktails, and homemade syrups
• Grow in a large pot (minimum 80 L) on a sunny alfresco terrace or balcony for fragrance, summer flower interest, and a culinary harvest without a full garden bed
• Combine with Westringia fruticosa, Callistemon, and Melaleuca for a cohesive low-maintenance native screen with year-round colour and exceptional wildlife value

Why You Will Love It

There is a reason Lemon Myrtle is called the queen of the lemon herbs — one brush of a leaf fills the air with the cleanest, brightest citrus scent you will ever encounter, richer and purer than any lemon in a bowl. Then come the flowers: a long, generous flush of creamy white fluff from late spring into summer that bees and butterflies simply cannot resist. In an Adelaide garden it earns its place as a hardworking screen, a sensory showpiece, and a year-round kitchen staple, all in one long-lived Australian native. Plant it where you walk past it every day and you will never regret it.