Lemon-Scented Gum

Native to northeastern Australia, primarily in Queensland.

• Found in the tropical and subtropical regions of Queensland, from the Atherton Tablelands south to the Brisbane area
• Also occurs in small populations in northern New South Wales
• Found at elevations from sea level to approximately 800 meters
• Grows in open forests and woodlands on well-drained soils
• The species name "citriodora" means "lemon-scented" in Latin
• Reclassified from Eucalyptus to the genus Corymbia in 1995, based on genetic analysis
• Widely planted across Australia and in many warm countries worldwide, including California, the Mediterranean, Africa, and India
• A beloved street and park tree in Australian cities
• The lemon-scented essential oil has been commercially harvested since the 19th century
• Oil production is centered in Queensland, Brazil, and China

A tall, graceful evergreen tree with an exceptionally beautiful trunk.

Bark:
• Exceptionally smooth, powdery, and uniform — among the most attractive bark of any tree
• Pure white to pale gray, often with patches of coppery-pink or pale green
• Powdery surface rubs off on touch (like talcum powder)
• Sheds in thin, curling flakes to maintain its pristine appearance

Leaves:
• Adult leaves alternate, narrowly lanceolate, 10 to 20 cm long and 1 to 2.5 cm wide
• Dark green and glossy above, paler beneath
• Rich in essential oil — crushed leaves emit a strong, clean lemon scent (citronellal)
• Juvenile leaves are broader, rougher, and even more strongly scented
• Aromatic oils are strongest in young foliage

Flowers:
• Produced in terminal clusters (corymbs) — a feature that distinguishes Corymbia from Eucalyptus
• Small, white to cream, with numerous conspicuous stamens
• Bloom in winter to spring
• Rich in nectar

Fruit:
• Small, urn-shaped capsules, 8 to 12 mm
• Contain tiny seeds

Form:
• 25 to 40 meters tall with a slender, straight trunk
• Crown relatively narrow and open
• Trunk diameter commonly 40 to 80 cm
• Overall impression is tall, slender, and elegant

The Lemon-Scented Gum is an ecologically important tree in Queensland forests and a valuable nectar resource.

Habitat:
• Found in open forests and woodlands on well-drained soils in tropical and subtropical Queensland
• Prefers warm, moist conditions but tolerates seasonal drought
• Grows on a variety of soil types including sandy loams and gravelly soils

Ecological interactions:
• Flowers produce abundant nectar — important food for honeyeaters, lorikeets, and gliding possums
• Koalas will feed on the leaves, particularly young regrowth foliage
• Provides roosting habitat for birds and bats
• The strong essential oils in the leaves may deter some insect herbivores

Essential oil ecology:
• Leaves contain 5 to 8% essential oil, dominated by citronellal (60 to 80%)
• Citronellal is a natural insect repellent that may protect the tree from herbivorous insects
• The oil may also inhibit the growth of competing plants (allelopathy)

Growth:
• Fast-growing, adding 1.5 to 2.5 meters per year in height when young
• Moderate lifespan of 100 to 200 years
• Develops a lignotuber that allows regeneration after fire
• Very drought-tolerant once established

A stunning ornamental tree for warm, dry climates.

Site selection:
• Full sun
• Well-drained soils — tolerates poor, sandy soils and rocky sites
• Very drought-tolerant once established
• Excellent specimen tree for large landscapes, streets, and parks
• Avoid planting near underground pipes — roots can be invasive

Planting:
• Plant container-grown or tube stock in spring or at the onset of the rainy season
• Tolerates a wide range of soil types if well-drained

Care:
• Water during the first dry season
• Very drought-tolerant once established
• Minimal pruning needed
• Generally pest-free
• Susceptible to Myrtle Rust (Austropuccinia psidii)
• Can be damaged by severe frost when young
• Hardy in USDA zones 9 to 11

The Lemon-Scented Gum is valued for its ornamental beauty, essential oil, and insect-repelling properties.

Essential oil:
• Leaves are the primary commercial source of citronellal, the key ingredient in natural insect repellents
• Lemon-scented eucalyptus oil is used in mosquito repellents, soaps, perfumes, and cleaning products
• More effective at repelling mosquitoes than standard eucalyptus oil
• Commercially produced in Australia, Brazil, China, and India

Ornamental:
• One of the most beautiful and widely planted ornamental eucalypts
• Spectacular smooth white bark creates a stunning visual feature
• Lemon fragrance fills the air, especially after rain
• Excellent shade and specimen tree for warm-climate landscapes

Timber:
• Hard, strong, durable wood
• Used for construction, poles, and fencing in Australia
• Suitable for tool handles and heavy construction

Traditional uses:
• Indigenous Australians used the leaves for medicinal purposes — treating respiratory infections and fever
• Leaves used as a natural insect repellent by placing branches in dwellings
• Crushed leaves applied to skin as a mosquito deterrent