Lemon myrtle (Backhousia citriodora) is an evergreen Australian native tree with strongly lemon-scented leaves. Lemon myrtle tree height in a Sydney garden depends on soil, shelter and pruning, and it stays far shorter than the rainforest trees it comes from if you shape it as a screen or large shrub.
This guide covers size, varieties, planting, care and pruning, plus when to call an arborist.
Key points
- Mature size varies by site and pruning, so treat any figure as indicative and check the nursery label for your plant.
- Lemon myrtle likes sun to part shade, moist well-drained soil, shelter from frost and wind, and regular water while young.
- Maintenance is moderate: mulch, water in dry spells, and tip-prune each year to keep a bushy shape.
- Watch for myrtle rust, a fungal disease of the myrtle family, and check council rules before removing or heavily pruning a large tree.
Lemon myrtle tree height at a glance
The table lists the usual garden traits. Sizes are indicative only, because nursery stock and local conditions differ.
| Trait | Detail |
|---|---|
| Botanical name | Backhousia citriodora |
| Type | Evergreen tree or large shrub, native to Queensland rainforest |
| Mature height in gardens | Commonly 3 to 8 m in cultivation (indicative — check the plant label) |
| Mature width | Commonly 2 to 4 m (indicative — check the plant label) |
| Sun | Full sun to part shade, with best growth in bright, sheltered spots |
| Soil | Moist, well-drained, slightly acidic, rich in organic matter |
| Water | Regular while young; tolerates short dry spells once established |
| Frost tolerance | Young plants are frost tender, so shelter them in western Sydney and the Blue Mountains |
| Flowering | Creamy white flower clusters in summer, usually December to February |
| Native? | Yes, Australian native |
Lemon myrtle tree size and varieties
Sellers use several names for the same plant, which causes confusion when you compare sizes.
| Name or form | Size | Best use | Notes |
|---|---|---|---|
| Lemon myrtle tree (standard) | 3 to 8 m high (indicative) | Feature tree or screen | Grows tallest in rich, moist, sheltered soil. |
| Lemon myrtle shrub (hedged form) | 2 to 3 m high (indicative) | Hedge or screen | Regular tip pruning keeps it bushy and low. |
| Backhousia citriodora dwarf or compact selections | 1.5 to 3 m high (indicative) | Pots, courtyards, small gardens | Ask the nursery which cultivar you are buying and read its label. |
| Myrtle lemon (potted tubestock) | Small when sold (indicative) | Starting a new planting | Pots are slow at first, then speed up in warm months. |
| Lemon ironwood | Same species as lemon myrtle | Searches and older plant labels | A regional common name, so check the botanical name on the tag. |
Where to plant lemon myrtle in Sydney
- Choose a sunny or lightly shaded spot with shelter from cold southerlies, because frost and strong wind burn new growth.
- Space plants about 2 to 3 m apart for a screen, or give a single tree 3 to 4 m clearance (indicative — check the label).
- Pick soil that drains but holds moisture; in heavy western Sydney clay, dig wide and mound the planting area.
- On sandy coastal soils, add compost and mulch generously, since lemon myrtle dislikes drying out.
- Pots suit small courtyards, but they need larger containers over time and more frequent watering.
- Keep it clear of pipes, paths and drains, because a mature tree has a wide root zone.
How to plant lemon myrtle
- Plant in autumn or spring (March to May or September to November), when soil is warm and rain is likely.
- Soak the pot until bubbles stop, so the root ball is wet before it goes in the ground.
- Dig a hole about twice as wide as the pot and no deeper than the root ball (indicative).
- Loosen circling roots gently, and tease the outer roots outward.
- Set the top of the root ball level with the soil surface and backfill without burying the trunk.
- Water slowly and deeply, using a hose with an on-off nozzle and following Sydney Water’s Water Wise Guidelines.
- Mulch with a layer of organic material, keeping it clear of the trunk.
- Stake only if the plant is exposed, and remove the stake after the first year.
Caring for lemon myrtle
| Task | When | How |
|---|---|---|
| Watering | Year-round, more in summer | Water deeply before 10 am or after 4 pm; drip irrigation may run between 10 am and 4 pm. |
| Feeding | Spring and early summer | Use a native or slow-release fertiliser exactly as the label directs. |
| Mulching | Autumn or spring | Top up organic mulch and keep it off the trunk. |
| Pruning | After flowering, late summer | Tip-prune to thicken growth and control height. |
| Pest and disease watch | All year, especially warm humid months | Look for orange-yellow powdery spots on new growth and check NSW DPI myrtle rust advice; for insects, book a licensed pest controller. |
| Frost cover | Winter, first years | Cover young plants on frost nights or move potted plants under cover. |
Pruning lemon myrtle to control tree height
Lemon myrtle tree height is easiest to manage when you prune lightly and often rather than cutting hard once.
- Tip-prune new growth every year after flowering to thicken the canopy and keep the plant at head height for easy picking.
- Use clean, sharp secateurs for small stems, and take no more than about a third of the foliage in one session (indicative).
- Cut just above a leaf node, so new shoots grow outward instead of crossing through the centre.
- Do not use a chainsaw above head height or work near power lines; book a qualified arborist for large trees.
- Check your council’s tree rules before heavy pruning or removal, since approval may be required above set sizes.
- Expect to pay $230 to $1,375 per tree for professional pruning in Sydney (typical $520), incl GST (October 2026).
Common lemon myrtle problems
| Symptom | Likely cause | Fix |
|---|---|---|
| Yellow leaves | Waterlogging, poor drainage or low nutrients | Improve drainage, mulch, and feed as the label directs. |
| Scorched new growth | Frost or hot, drying wind | Shelter the plant, and prune off damaged tips after the cold passes. |
| Orange or yellow powdery spots | Myrtle rust | Contact NSW DPI for current guidance and avoid spreading spores on clothing or tools. |
| Leggy, sparse growth | Too much shade or too little pruning | Move to more light and tip-prune each year. |
| Leaf drop in summer | Drought stress | Water deeply and mulch, within water restrictions. |
| Slow growth | Poor soil or root-bound pot | Loosen roots and add compost around the root zone. |
FAQ: lemon myrtle tree height questions
How tall does a lemon myrtle tree grow?
In rainforest it can become a tall tree, but in gardens it is usually much shorter, depending on soil, shelter and pruning (indicative — check the plant label). Annual tip pruning keeps it at a manageable height and gives denser foliage.
What is a lemon myrtle shrub and is there a dwarf Backhousia citriodora?
A lemon myrtle shrub is simply a plant kept small by regular pruning. Some nurseries sell compact selections of Backhousia citriodora labelled dwarf, but check the label for expected size and growth habit.
Is lemon ironwood the same as lemon myrtle?
Lemon ironwood is a common name used for the same species, Backhousia citriodora. Always confirm the botanical name on the plant tag, and positively identify any leaf before you eat it or use it in cooking.
Can I grow lemon myrtle in a pot?
Yes. Use a large container with drainage holes, quality potting mix and mulch, and water more often than a ground planting. Expect a smaller plant, and repot into a larger pot when roots circle the base.
Keeping lemon myrtle at the right height in Sydney
If your lemon myrtle has outgrown its spot, we can shape it, thin the canopy and remove green waste, and refer large trees to a qualified arborist. Read our pruning guide first, or book tree pruning in Sydney for an itemised quote.
