Smooth-barked apple (Sydney red gum) Angophora costata
Smooth-barked apple (Sydney red gum) (Angophora costata) is an evergreen perennial tree in the Myrtaceae family, native to Eastern Australia, on the sandstone of the Sydney region and coastal Queensland. It grows 15–25 m (49–82 ft) tall and 10–15 m (33–49 ft) wide, wants full sun and low water, and is hardy to about -4 °C (25 °F). Space plants about 12 m (39 ft) apart.
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Smooth-barked apple (Sydney red gum) at a glance
| Type | Perennial tree, evergreen |
|---|---|
| Family | Myrtaceae |
| Mature height | 15–25 m (49–82 ft) |
| Mature spread | 10–15 m (33–49 ft) |
| Spacing | 12 m (39 ft) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 4.5–6.5 |
| Cold hardiness | About -4 °C (25 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 40 °C (104 °F) |
| Flowering | about 261–417 weeks after planting, for 4–7 weeks |
| Wind tolerance | Moderate |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Eastern Australia, on the sandstone of the Sydney region and coastal Queensland |
| Common in gardens of | 🇦🇺 Australia, 🇺🇸 United States, 🇳🇿 New Zealand |
Is Smooth-barked apple (Sydney red gum) toxic?
- People: mildly toxic
- Cats: mildly toxic
- Dogs: mildly toxic
- Parts: leaves, essential oil
Eucalyptus oil is poisonous if swallowed (drooling, vomiting, drowsiness); keep the oil away from children and pets.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Smooth-barked apple (Sydney red gum)
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Keep apart or take care
- caution With Guava: Myrtle rust (Austropuccinia psidii) infects guava, feijoa, Surinam cherry and many other Myrtaceae; it spreads by airborne spores between them. Evidence B
Questions about Smooth-barked apple (Sydney red gum)
- How far apart should I plant Smooth-barked apple (Sydney red gum)?
- About 12 m (39 ft) apart, centre to centre. A mature plant spreads 10–15 m (33–49 ft).
- Does Smooth-barked apple (Sydney red gum) need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Smooth-barked apple (Sydney red gum) need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Smooth-barked apple (Sydney red gum)?
- It tolerates about -4 °C (25 °F) once established, roughly USDA zone 9.
- When does Smooth-barked apple (Sydney red gum) flower?
- About 261–417 weeks after planting, for 4–7 weeks.
- Is Smooth-barked apple (Sydney red gum) poisonous to cats and dogs?
- For cats it is mildly toxic; for dogs mildly toxic; for people mildly toxic. Eucalyptus oil is poisonous if swallowed (drooling, vomiting, drowsiness); keep the oil away from children and pets.
- What grows well with Smooth-barked apple (Sydney red gum)?
- There is no well-documented companion pairing for Smooth-barked apple (Sydney red gum). Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- PlantNET: the NSW Flora Online, National Herbarium of New South Wales, Botanic Gardens of Sydney
- Australian native plant profiles, Australian National Botanic Gardens / Australian Plants Society
Notes and assumptions
- An Australian native of poor, sandy soils: it wants sharp drainage and sun, and rots in heavy, wet ground or humid summers.
- Twisted, dimpled limbs with smooth bark that peels in late spring to reveal fresh salmon-pink beneath, fading to grey; one of the most painted trees of the Sydney bush. Cream flowers in early summer bring flocks of lorikeets. A close relative of the eucalypts.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Lemon myrtle Backhousia citriodora
- Guava Psidium guajava
- Feijoa Acca sellowiana
- Surinam cherry (pitanga) Eugenia uniflora
- Cider gum (eucalyptus) Eucalyptus gunnii
- Lilly pilly Syzygium smithii
- Crimson bottlebrush Melaleuca citrina
- Mānuka (tea tree) Leptospermum scoparium