Lemon Myrtle

Lemon Myrtle is endemic to the coastal and sub-coastal regions of southeastern Queensland and northeastern New South Wales, Australia.

• Its natural range extends from the Maryborough–Bundaberg region of Queensland southward into northeastern New South Wales
• It is primarily found in subtropical rainforest ecosystems, particularly in rich, moist gullies and on fertile alluvial or basalt-derived soils along watercourses
• Indigenous Australian peoples, particularly the Aboriginal groups of southeastern Queensland, used lemon myrtle leaves for culinary and medicinal purposes for thousands of years before European settlement
• European recognition of the plant began in the mid-19th century; the species was formally described by the renowned Australian botanist Ferdinand von Mueller in 1853
• Commercial cultivation of lemon myrtle began in earnest in the 1990s as interest in Australian native bushfoods grew, with plantations established in Queensland and northern New South Wales

Lemon Myrtle is a medium-sized evergreen tree, typically reaching 3 to 8 meters in height in cultivation, though it can grow up to 20 meters in its native rainforest habitat.

Bark & Branches:
• Bark is grey to grey-brown, rough and somewhat flaky on mature trees, becoming smoother on younger branches
• Young branchlets are slender, often slightly four-angled, and covered with fine soft hairs when new

Leaves:
• Arranged in opposite pairs along the stem
• Simple, entire, lanceolate to elliptic, measuring 7–13 cm long and 1.5–3 cm wide
• Glossy dark green above, paler beneath, with prominent oil glands visible as translucent dots when held up to light
• Margins are entire (smooth-edged); apex is acuminate (tapering to a point)
• When crushed, leaves release an intense, pure lemon fragrance due to extremely high citral content (approximately 90–98% of essential oil composition)
• Petioles (leaf stalks) are short, approximately 5–10 mm long

Flowers:
• Produced in dense, showy terminal clusters (cymes or panicles)
• Individual flowers are small (~5–7 mm diameter), white to creamy-white, with five rounded petals
• Numerous prominent stamens give the flower clusters a fluffy, starburst appearance
• Flowering typically occurs in late spring to early summer (approximately October to December in the Southern Hemisphere)

Fruit:
• Small, dry, cup-shaped capsules (~3–4 mm diameter)
• Capsules split open at maturity to release numerous tiny seeds
• Seeds are minute, approximately 1 mm long, and dispersed primarily by wind and gravity

In its native habitat, Lemon Myrtle occupies a specific ecological niche within subtropical and dry rainforest communities.

Habitat:
• Prefers well-drained, fertile soils derived from basalt or alluvial deposits
• Found in moist gullies, along creek margins, and on lower slopes of coastal ranges
• Typically grows as an understorey or mid-canopy tree in association with other rainforest species such as Ficus, Araucaria, and various Lauraceae

Climate:
• Thrives in warm, humid subtropical climates with annual rainfall of approximately 1,000–1,600 mm
• Tolerant of light frost once established, though young plants are frost-sensitive
• Optimal temperature range: 15–30°C

Pollination & Seed Dispersal:
• Flowers attract a variety of insect pollinators, including native bees, honeybees, and hoverflies
• The abundant nectar and pollen make it a valuable plant for supporting pollinator populations
• Seeds are small and light, dispersed by wind and gravity; germination is generally reliable in moist, warm conditions

Ecological Role:
• Provides food and habitat for native insects and birds
• Its dense canopy offers shelter for small vertebrates
• Plays a role in rainforest regeneration and understorey diversity

Lemon Myrtle has become one of the most widely cultivated Australian native plants, valued both as an ornamental garden specimen and as a commercial crop for its essential oil and culinary leaves.

Light:
• Prefers full sun to partial shade; best leaf oil production occurs in full sun
• In very hot climates, some afternoon shade can prevent leaf scorch

Soil:
• Requires well-drained, fertile soil; tolerates a range of soil types from sandy loam to clay loam
• Optimal pH: slightly acidic to neutral (5.5–7.0)
• Does not tolerate waterlogged conditions; good drainage is essential

Watering:
• Regular watering during establishment (first 1–2 years)
• Once established, moderately drought-tolerant, though consistent moisture promotes better leaf growth and oil production
• Mulching around the base helps retain soil moisture and regulate root temperature

Temperature:
• Hardy in USDA zones 9–11
• Can tolerate brief light frosts (down to approximately -2°C) once mature
• Young plants should be protected from frost
• In cooler climates, lemon myrtle can be grown in large containers and moved indoors during winter

Pruning:
• Responds well to regular pruning, which encourages bushy growth and increases leaf yield
• Can be maintained as a hedge or shaped as a small ornamental tree
• Pruning after harvest promotes vigorous new growth

Propagation:
• Primarily propagated by seed, which germinates readily in warm, moist conditions (germination typically within 2–4 weeks)
• Can also be propagated by semi-hardwood cuttings taken in late summer, though rooting may be slower
• Seed-grown plants generally develop a stronger root system

Common Problems:
• Generally pest-resistant due to high citral content, which acts as a natural insect repellent
• Occasionally susceptible to myrtle rust (Austropuccinia psidii), a fungal disease affecting many Myrtaceae species
• Root rot can occur in poorly drained soils
• Scale insects may occasionally appear on stressed plants