How to Grow Australian grass tree
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Australian grass tree
Xanthorhea australis
treeA distinctive evergreen tree native to southeastern Australia, characterized by a stout, dark trunk topped with a dense crown of long, narrow, grass-like leaves. It produces tall spikes of fragrant white or cream flowers and is an iconic ornamental in native Australian gardens. Known for extreme longevity, some specimens are estimated to be over 600 years old.
When should you plant Australian grass tree in your zone?
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Example Australian grass tree timeline · Pittsburgh, PA (Zone 6b)
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Plant Australian grass tree
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Australian grass tree
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Australian grass tree dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in USDA zones 9b-11; can survive in zone 9a with protection
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Get my Australian grass tree timeline →Growth Stages
Establishment
2-3 yearsYoung plant with emerging rosette of grass-like leaves; minimal trunk development
Water regularly but allow soil to dry between waterings; protect from frost; ensure excellent drainage; avoid fertilizing
Maturation
OngoingSubstantial trunk with characteristic dark bark; full-sized crown of narrow leaves reaching 2-4 feet long
Water only during extended drought; no fertilizing needed; remove any dead fronds manually; very low maintenance
Flowering
6-8 weeksDense spike of small, fragrant white or cream flowers emerges from crown center, appearing as a tall column
Do not interfere with flower spike; allow to develop naturally; flowering occurs annually once mature, usually spring to early summer
Seed Development
Several monthsFlower spike matures and develops seed capsules; eventually dries and can persist on tree for extended period
Allow seed pods to dry naturally; collect seeds if desired for propagation; dead flower spikes eventually fall naturally
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Ensure excellent soil drainage; avoid overwatering; plant in raised bed if in humid climate; remove affected plants if infection occurs
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Spray with horticultural oil in early stages; remove heavily infested leaves; usually not a serious problem
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Remove affected leaves; ensure good air circulation; avoid overhead watering
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Spray with insecticidal soap; prune out heavily affected areas; rarely requires intervention on mature plants
Uses
Distinctive landscape focal point
OrnamentalThe dramatic silhouette and unique form make Xanthorhea australis an iconic specimen tree for xeriscaping and native Australian gardens. Its sculptural appearance and year-round foliage provide architectural interest in dry landscape designs. [source]
Nectar source and shelter
WildlifeThe fragrant flowers attract native bees, honeyeaters, and other pollinators. The dense foliage crown provides shelter and nesting sites for native birds and small mammals. [source]
Traditional material uses
HouseholdIndigenous Australians traditionally used the leaf fibers for weaving baskets, mats, and cordage. The resinous trunk material was used in historical times for various practical applications. [source]
Traditional ethnobotanical uses
MedicinalSome traditional Aboriginal uses recorded for medicinal purposes, though scientific validation is limited. Modern research explores potential anti-inflammatory and antimicrobial properties of resin compounds. [source]
Extreme drought and fire tolerance
DroughtExceptionally adapted to dry conditions and naturally fire-prone environments. Useful in water-conservation gardens and climate-resilient landscaping in Mediterranean and semi-arid climates. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Seeds can be collected from mature seed pods once they dry and darken (typically 8-12 months after flowering). Cut or remove the dried flower spike and extract seeds. Viable seeds are dark and firm. Fresh seeds have higher germination rates than stored seeds, but seeds can be stored dry in cool conditions for extended periods.
Fun Facts
- 🌱 Xanthorhea australis is one of the longest-living flowering plants on Earth, with some individual trees documented to be over 600 years old, and potentially living much longer.
- 🌱 The name 'grass tree' is somewhat misleading; despite its grass-like leaves, it is actually a monocot tree more closely related to palms and yuccas than to true grasses.
- 🌱 The tree produces an aromatic resin that is highly flammable; in its native Australian bushfire environment, the intense heat can trigger spontaneous flowering as a survival strategy.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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