Corymbia citriodora: The Lemon-Scented Gum Behind the Oil
Corymbia citriodora is the lemon-scented gum, a tall, smooth-barked tree from Queensland, Australia. It was classified as Eucalyptus citriodora until 1995, when it was moved to the genus Corymbia. Its leaves yield an oil that is often rich in citronellal, which is the source of both lemon eucalyptus essential oil and, after refining, the PMD used in registered repellents.
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Shop Now →A tree is easy to describe badly. Descriptions of this one tend to repeat each other, and sources that look authoritative disagree on basic points such as where it grows naturally and how tall it gets. This page sticks to what botanical and plant-resource references say, shows where they differ, and then connects the tree to the bottle. For the oil itself, our complete guide to lemon eucalyptus oil is the companion piece.
Getting the name right
The accepted name is Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson. The parentheses show that Hooker described the tree first, as Eucalyptus citriodora in 1848. K.D. Hill and L.A.S. Johnson moved it into Corymbia in a 1995 paper in the botanical journal Telopea, according to the Royal Botanic Garden Sydney's PlantNET. The plant-resource handbook PROSEA lists two more names that appear in older literature: Eucalyptus melissiodora (Lindley, 1848) and Eucalyptus maculata var. citriodora (1900). Its common names include lemon-scented gum and spotted gum.
For a buyer, the practical point is that the old name has not vanished. Scientific papers and supplier labels use both, and a 2006 mosquito repellent review still flagged the "updated nomenclature" for the tree. If a label says Eucalyptus citriodora, it is the same species. The Australian National Botanic Gardens notes that citriodora means "lemon-scented."
What the tree looks like
The references agree on the character of the tree and differ a little on the numbers.
| Feature | PlantNET (Royal Botanic Garden Sydney) | PROSEA (plant-resource handbook) | Australian National Botanic Gardens |
|---|---|---|---|
| Height | Tree to 50 m | Typically 25 to 40 m, sometimes up to 50 m | Can exceed 40 m in the wild, usually 20 to 30 m in cultivation |
| Bark | Smooth, white to pink or coppery, often powdery, shedding in thin curling flakes | Pale grey, cream or pink, powdery, smooth throughout, peeling in flakes | Smooth, white, pink or blue-grey, shedding in thin curly flakes in spring |
| Leaves | Narrowly lanceolate to falcate; "lemon-scented when crushed or not so" | 7 to 22 cm by 0.5 to 2.2 cm, very glossy green, strongly lemon-scented when crushed | Strongly lemon-scented |
| Natural range | Cooktown area to south of Gladstone, Queensland | Main range from north-west of Maryborough to north of Rockhampton | Dry ridges and plateaux of coastal sub-tropical Queensland |
Two details are worth pausing on. First, the natural range is described three different ways, from a long northern stretch to a narrower central one. We would trust the broad statement, that the tree is a Queensland native of coastal and hilly country, over any precise place name. Second, PlantNET's wording "lemon-scented when crushed or not so" is a botanist's hint that scent is not guaranteed in every individual tree. That leads to the most important idea for anyone buying the oil.
Why the oil varies from tree to tree
PROSEA reports that citronellal content in the leaf oil varies by type. Across natural Australian stands it ranges from 1% to 91%, and the citronellal-rich types, the ones that produce what the trade calls lemon eucalyptus oil, contain 65% to 91%. So "lemon eucalyptus oil" is not one fixed composition. It is what you get when high-citronellal trees are harvested and distilled, and it depends on the stock, the season and the process.
That is why we point buyers to the numbers on a certificate and not to the tree's name. Our guides on how to tell whether lemon eucalyptus oil is pure and on reading a label and GC/MS report take that further. For how citronellal gives the oil its character, see the citronellal explainer.
Where it grows and how it spread
PlantNET places the tree in dry sclerophyll forest and woodland in hilly country, on lighter loamy or skeletal soils, and describes it as sparingly naturalised in New South Wales. The Australian National Botanic Gardens adds that it is naturalised further inland in Queensland and in Western Australia, South Australia, New South Wales and Victoria. PROSEA records the species as a member of the myrtle family (Myrtaceae) with 22 chromosomes in its cells (2n = 22) and calls it a popular ornamental. In plain terms, the tree has left its native ground and now persists in several Australian states, which is one reason botanical records mix "native" and "naturalised" ranges.
From a Queensland native to a worldwide crop
PROSEA, published in 1999, describes the tree as planted commercially in Brazil (about 6 million trees at that time), southern China, India, Sri Lanka, Congo, Kenya, most of southern Africa and Fiji. It also notes that Thailand introduced the species in 1949 but no commercial plantations remain there. That handbook is old, so treat the country list as a map of where the tree has been grown, not a current production table.
The same source gives yields that explain why growers coppice the trees, cutting them back to regrow. Fresh leaves hold 0.5% to 5.0% oil, mostly in the 1% to 3% range. A coppiced plantation of 2,000 stems per hectare is estimated at about 150 kg of oil per hectare per year. The Australian National Botanic Gardens adds that the tree can grow up to 2 m a year and that a 20 m tree can be expected within ten years, which fits its use as a plantation crop.
What the leaves become
| Product | What it is | Source for the description |
|---|---|---|
| Steam-distilled leaf oil | The essential oil, valued by the fragrance industry. Citronellal-rich oil is also a preferred source for chemicals such as hydroxycitronellal and menthol. | PROSEA |
| PMD and refined oil of lemon eucalyptus | PMD is described as a spent product of the distillation of the leaves and is the active ingredient in registered repellents. | Carroll and Loye, 2006 |
| Timber | A strong structural timber used for beams, bridges, poles, flooring and tool handles. | Australian National Botanic Gardens |
| Ornamental and nectar tree | Planted for its form and as a nectar source for bees. | PROSEA |
The second row is the one people confuse with the first. Our oil is the first row. It is not the refined PMD ingredient, and it is not a registered repellent. CDC lists oil of lemon eucalyptus and PMD among recommended active ingredients only in EPA-registered products, and says it does not recommend "pure" lemon eucalyptus oil as a repellent. The difference is covered in OLE versus lemon eucalyptus essential oil and in our OLE guide.
How to read a botanical reference
Three habits help when you meet a figure for height, range or oil content. First, note whether the number describes wild trees or cultivated ones; the Australian National Botanic Gardens separates the two and gives 20 to 30 m for cultivated trees against more than 40 m in the wild. Second, note the publication date, because PROSEA's 1999 plantation figures describe a past picture. Third, expect ranges, not single values, for anything chemical. PROSEA's 0.5% to 5.0% oil yield and its 1% to 91% citronellal spread are the honest way to describe a living crop, and a source that gives one tidy number has probably averaged the variation away.
How the leaves become oil
Steam distillation is the standard route from leaf to essential oil: steam passes through the leaves, carries the aromatic compounds off, and condenses into oil and water that are separated. Our walk-through of how lemon eucalyptus oil is made covers it in detail. The point to keep from this page is that what comes out reflects what went in. A high-citronellal chemotype distilled well gives the bright, lemony, green top note people buy it for. You can read how that smells in our scent profile.
What we do and do not claim
We sell one product, Lemon Eucalyptus Essential Oil, from Corymbia citriodora leaf, steam distilled and bottled 100% pure and undiluted, with high natural citronellal. We do not describe the plantations, harvest or distillation behind our bottle on this page, because this article is about the species, not our supply chain. Our oil is an aromatic ingredient for fragrance, candle, soap and diffuser work. You can see the sizes in the shop.
Frequently asked questions
Is lemon eucalyptus the same tree as ordinary eucalyptus?
No. Lemon eucalyptus is Corymbia citriodora, moved out of Eucalyptus in 1995. Our guide to lemon eucalyptus versus eucalyptus oil compares the oils.
Do all lemon-scented gums smell the same?
No. PlantNET itself says the leaves are lemon-scented "when crushed or not so," and PROSEA reports citronellal in the oil ranging from 1% to 91% across natural stands.
Where does the tree grow naturally?
In Queensland, on dry ridges, plateaux and hilly country, according to PlantNET, PROSEA and the Australian National Botanic Gardens, though they describe the exact range differently.
Last reviewed: October 2026
Lemon Eucalyptus Essential Oil
Lemon Eucalyptus Essential Oil from our own shop, in sizes from 0.5 oz to bulk.
From $9.99
Shop Now →Sources & Further Reading
- PlantNET: Corymbia citriodora, Royal Botanic Garden Sydney
- PROSEA: Corymbia citriodora (Doran, 1999)
- Australian National Botanic Gardens: Corymbia citriodora
- Carroll SP, Loye J. PMD, a registered botanical mosquito repellent with deet-like efficacy. J Am Mosq Control Assoc, 2006
- CDC Yellow Book: Mosquitoes, Ticks, and Other Arthropods