Lemon Scented Gum (Corymbia citriodora) Growing Guide

What is Lemon Scented Gum?

Lemon scented gum is a native tree, reaching up to 50m tall, though generally no more than 20m in open spaces and gardens. Its smooth bark tends to be vibrantly white with a uniform colouring, and very occasional copper-coloured flaking bark.

Adult plants that are left unpruned have slightly curved lanceolate leaves with a glossy green colouring, while the foliage of coppiced lemon scented gum, or young trees is straight, more uniform and sharply pointed, with colouring similar to most Eucalyptus (blue-green on one side, silver-green on the base). 

They are grown mostly for their ornamental value, and their seeds, flowers and foliage have no edible uses, and while foliage is often used in home remedies it is not as effective as true Eucalyptus leaves for the same treatments.

Natural Habitat of Corymbia citriodora

Lemon scented gum is only found in north-eastern Australia where it grows in tropical forests and humid temperate forests. In both cases, it is found growing on rich, heavy soil typically over 80m above sea level.

The moisture-retentive soils of its native habitat provide a clue to its cultivated preferences, in that it can cope well with droughts, but prefers to have moisture and nutrients at its feet all year round where possible.

That makes it ideal for damp soils, but problematic for some very sandy or dry clay soils.

Common Uses for Lemon Scented Gum

Lemon scented gum is a particularly useful plant for insect and tick bites, as well as for use as a repellent. Its citrussy odour works generally to repel mosquitoes and wasps but has active pest repelling functions too.

Like Eucalyptus, Corymbia shares antiseptic properties and can be used to soothe and clean bites, as well as drying them out to reduce swelling and inflammation.

Identifying Corymbia citriodora

Corymbia citriodora, formerly Eucalyptus citriodora, is an incredible example of plant classification, not just based on outward characteristics, but on the functions of reproduction. By all intents and purposes, C. citriodora could be a Eucalyptus. In fact, until not so long ago it was.

However, the flowers are significantly larger than most eucalyptus, with more open centres. The resulting seed pods (gum nuts) are filled with a fraction of the number of seeds, and those seeds are significantly larger than Eucalyptus too.

Both are members of the myrtle family and share characteristics with myrtles and other Eucalyptus species, but the distinct beauty of these highly ornamental Corymbia citriodora trees sets them apart from anything else found native to this unique and wonderful country. 

How to Grow Lemon Scented Gum

Lemon scented gum is shockingly simple to grow, but you really will need to pay close attention to your soil conditions before planting. Thankfully, it's quite intuitive, and you definitely don’t need any test kits, or complicated gear to find the right spot for this spectacular native tree.

Follow this growing guide below for perfect results when starting your own lemon scented gum, whether it's from seed, a semi-mature tree, or a sapling. There are hints and tips for every size and stage.

Ideal Conditions for Growing Corymbia citriodora

Before you get started, get to know the preferred conditions of these gorgeous native trees. If you’ve read the section above about their native habitat, you’ll know that they’re not afraid of moisture, and certainly not picky about nutrients. 

Soil & Drainage

Lemon scented gum trees are happy to grow on a wide range of soils, with no real preference for acidic or alkaline. Grown in a typical garden soil with slightly acid to neutral soil, your Corymbia citriodora should truly thrive.

Start with any reasonably moisture-retentive loam, and you won’t go wrong. If you’ve got very loose sandy soil, or poor, nutrient-depleted soil, add plenty of organic matter. Even boggy conditions can be suitable provided the moisture isn’t stagnant. Wet, clay soils, if some loam or humus-rich compost is added, will offer exactly the right conditions too

It might sound like hard work, but it’s worth the effort. If you find that balance of drainage and moisture, you’ll have a completely self-reliant tree that will go on happily for centuries.

Light & Temperature

Lemon scented gum grows in full sun and part shade. Full shade can be challenging, but it will likely grow straight up until it reaches the light. For the best shape, plant in full sun where your Corymbia can develop a more even, open canopy.

Shelter

No shelter from the wind or coastal gusts is required, and lemon scented gum is hardy down to about -5°C once established. Young trees benefit from a light mulch in their first few winters if there is snow or frost expected.

Planting Lemon Scented Gum

When it comes to planting young lemon scented gums, where the trunk is no taller than 2m, and less than 10-15cm in diameter, it is a good idea to stake it, using a simple round tree-stake, and a rubber plant tie. This offers movement against the wind while the trunk hardens and the roots take hold.

Other than that, the usual rules for planting trees apply;

1. Dig a hole roughly twice the width of the root ball, and the same depth.
2. For sandy or clay soils, mix through plenty of leaf mould of lightly acidic organic matter.
3. Rub a handful of mycorrhizal fungi onto the root ball to improve root development.
4. Place the tree into the planting hole, and adjust the angle so it suits its setting.
5. Backfill the hole with amended soil, then firm in around the base of the tree.
6. For trees between 0.5 and 3m tall, add a firm stake and loose rubber tree-tie to protect against wind.
7. Drench the base of the tree, then mulch with chipped bark or compost.

Note: Corymbia citriodora is a very fast-growing tree, and can be planted as a tiny sapling. If you are planting any tree under 50cm tall there is no need to stake it, simply water well, mulch and leave it to do its thing. It will strengthen naturally with no need for other support, and reach several tall in a few short years.

How to Propagate Corymbia citriodora

Corymbia citriodora is really quite simple to propagate, and thanks to its larger seeds, is far easier to handle at this stage than any Eucalyptus. Because you get fewer seeds than with Eucalyptus, some cold stratification is useful, and while this sounds complex to beginners, it is actually pretty simple. All you need is a plastic bag, a fridge, and some patience.

And when it comes to propagating from cuttings, the similarities with Eucalyptus continue. Corymbia is just as challenging to grow from cut material, and requires some quite dedicated preparations. However, when you break it down, it uses fewer resources than most propagation.

Methods and tips for both types of Corymbia propagation are below:

Propagating Corymbia citriodora from Seeds

Before you start to prepare seed sowing materials, consider placing your lemon scented gum seeds in the fridge for a few weeks (temperatures below 5°C for five weeks improve germination rates remarkably well).

Then, remove your seeds from the fridge, and begin by sprinkling them out onto a sheet of white paper so you can keep track of them. Thankfully, the winged seeds of lemon scented gum are easy to handle.

Fill a seed tray with seed compost, and wet the compost all over. Sow the seeds directly on the surface of the moist compost, and place the tray in a propagator at 21°C, or in a warm spot outdoors. Germination takes several weeks, so be patient.

Note: You can sow seeds onto the compost tray, and then place the whole set up in the fridge, before placing it somewhere warm, which gives better soil contact, but for most of us, it isn’t a practical use of fridge space.

Propagating Corymbia citriodora from Cuttings

Cuttings are possible from Corymbia citriodora, but usually will take with a less than 10% success rate. If you are going to try standard cuttings, the best method we’ve found is to use pots filled with pure perlite, moistened, and then soft shoots with new buds in spring as the cutting material dipped in rooting gel.

Alternatively, look for suckers around the base of the plant. Sometimes these will root separately and can be cut away to grow as a separate tree.

How to Care for Lemon Scented Gum

Caring for lemon scented gum is one of the simplest things you’ll ever have to do, because once established they tend to do better the less you do to them.

These are tough native trees. Provided they are planted in the right spot, on the right soil, and with adequate space around them, there is very little you can do to improve their health.

However, despite being frost-hardy, drought tolerant, and happy in moist and dry conditions in equal measure, you should always keep an eye out for grey or anaemic foliage caused by overwatering.

It can be tricky to treat the cause of this for establishing lemon scented gum trees, but for potted ones, there are definitely ways to improve matters, which we’ll touch on in a moment. 

Pruning Lemon Scented Gum

First, though lemon scented gums are basic trees with basic needs, they don’t require pruning if you intend to grow them as large specimen trees in an open landscape. However, there are two very valid reasons to consider pruning these tough trees:

1. Coppiced lemon scented gums make an outstandingly fragrant hedge.
2. Mature lemon scented gums have incredibly dense canopies that will block light and can pose a risk when older limbs are caught in the wind.

Thinning out the lead branches as they develop will hopefully produce a more open shape, and more upright branches, which are stronger against wind as well as being less likely to decay as rainwater rolls away from them.

Coppicing is useful for creating informal hedgerows, but also a great way to make sure you can keep these massive trees contained in confined containers for longer.

Repotting Lemon Scented Gum

Coppiced lemon scented gums can be kept in pots for fragrance and structure on balconies, but they will only last for about ten years before they completely outgrow their space. Their roots are shallow and spreading, so even with regular pruning, you will only ever get ornamental but short-lived plants. 

That doesn’t mean it’s not worth doing, but you should be prepared to replace lemon scented gums in containers fairly regularly.

Lemon Scented Gum Pests and Diseases

Corymbia citriodora is a useful pest deterrent and will help to keep mosquitoes and spiders out of your garden, particularly if planted as a coppiced hedge around patios. However, it doesn’t share quite as many, or quite as effective an array of pest-deterring properties as its eucalyptus cousins.

For example, lemon scented gum is susceptible to termite attacks, eucalyptus moths and several fungal diseases that most infect and spread through damaged foliage and branches. Gall wasp, eucalyptus moth, etc. 

However once introduced outside of its natural habitat, the plant is known to be susceptible to termite invasions along with various diseases and pathogenic fungi such as leaf spot, rust, stem canker, root rot, and pink disease.

Lemon scented gum pests are general as well as specific, so as well as the list below, common garden pests like aphids and spider mites can infest new shoots. On mature trees, there are no pest species that will routinely cause significant damage to this species.

Gall wasp

Gall wasps are problematic on young trees, and will occasionally cause complete defoliation through over-infestation when populations are allowed to increase without natural predators present.

There are many garden insects that feed on the young larvae of gall wasps, and birds will eat the adults happily, so building a wild ecosystem of native creatures in your garden is the most effective way to stop this from happening.

When you do notice galls on the leaves, simply remove them and burn them to slow the spread of adult wasps.

Emperor gum moth

Eucalyptus moth, or the emperor gum moth, has a distinctive spiked caterpillar that is particularly associated with myrtles. It can eat several leaves per day and reaches up to 10cm long.

It is a problem for young lemon scented gums but should be left to its own devices on mature trees where it will rarely cause any real damage.

Termites

Termites are not a problem in the natural environment for Corymbia citriodora, but these trees do tend to fall victim to them on drier soils in gardens or parks, and termites are a potentially dangerous pest.

There are treatments available if you notice termite damage.

Diseases are not very common with lemon scented gum trees, but when they happen, it is nearly always due to damage or excessive and stagnant moisture around their base. Despite being moisture-loving plants that grow happily on heavy soils, they need that moisture to be transient, and to move one when it is replaced by new rainfall. 

As a result, very wet soils can cause lemon scented gums to develop root problems, and sometimes the overwatered roots will trigger other issues higher up the plant and foliage dry out, or become attractive to leaf-feeding insects.

Leaf spot

Leaf spot is nearly always a knock-on effect of common garden pests like thrips or mealybugs, but the actual cause is fungal. Different spot shapes, colourings and formations are signifiers of various funguses or viral causes.

In all cases, it's best to remove the leaves before the problem spreads, but other than rust, the issues can self-manage from year to year without doing too much harm to the tree.

Rust

Myrtle rust is a big problem in Australia now. It was first detected in New South Wales in 2010, and has spread across eastern Australia significantly ever since. 

In garden settings, there are things you can do to limit the spread, like removing and burning any signs of the fungus, but you should also report it to your local authority so that records of the spread can be properly recorded.

Lemon Scented Gum Frequently Asked Questions

What is the lemon scented gum good for?

Lemon scented gum is especially good for treating deer tick bites and as a mosquito deterrent, Its antifungal and antiseptic qualities make it a useful topical treatment for countless other ailments too.

How fast do lemon scented gums grow?

Lemon scented gums grow at a rate of almost 1m per year (90cm to be precise). This growth contributed to an overall height of up to 50m, though most will grow to 20-30m at most.

What is another name for lemon scented gum?

Citriodora, the species name of lemon scented gum, translates directly from Latin as ‘lemon-scented’ but it is sometimes called citrus scented gum, lemon gum and lemon eucalyptus.

What is the difference between spotted gum, and lemon scented gum?

Spotted gum is often confused for lemon scented gum, but the two have very different aromas. Lemon scented gum has a powerfully lemony scent, while spotted gum is virtually scentless. 

Are lemon scented gum leaves edible?

Lemon scented gum, Corymbia citriodora, is not an edible plant. It has several toxins present in its leaves that can cause severe digestive problems. There are some sources that suggest the dried leaves make a fragrant tea, and its use in medicine is in restricted amounts, but general consumption of any part is not advised. 

Is lemon scented gum a hardwood?

Lemon scented sum is an excellent hardwood, often used for flooring or as construction timber. It isn’t particularly resistant to termites, but it has a wonderfully rich finish that is easy to sand to an even texture.

What are the disadvantages of lemons scented gum?

Lemon scented gum is not safe to take by mouth and has even been reported to cause seizures in some users. As a plant, there are no real drawbacks other than the height, which restricts its use to larger gardens.

Is lemon scented gum invasive?

Lemon scented gum can be an invasive weed, spreading to Banksia woodland and overshadowing lower lying plants. Depending on where you live in Australia, consider planting alternatives like Coral Gum.

Is lemon scented gum good for wildlife?

In the right setting, lemon scented gum is a boon for wildlife, offering pollen and nectar for bees, birds, butterflies and other insects.

For more options, check out our collection of Eucalyptus to grow in Australia.