Australian Blackwood (Acacia melanoxylon) Growing & Care Guide for Gardeners
Article by Dean Ravenscroft, Ph.D. - Updated 31st Jan 2024
- Plant Characteristics: Acacia melanoxylon is known for its rich dark green foliage and its ability to grow into a large, elegant tree. A perfect addition for adding structure and elegance to your garden.
- Growing & Care: Thrives best in well-drained soil with regular watering, particularly in warmer climates. It's low maintenance but benefits from occasional pruning to maintain shape and health.
- Tips for New Gardeners: An excellent choice for beginners due to its hardiness and ease of care. Be cautious of its rapid growth; ensure ample space. While generally pest-resistant, keep an eye out for common garden pests.
Acacia melanoxylon is more commonly known as Australian Blackwood. Other names include Blackwood, Blackwood Acacia, and Tasmanian Lightwood.
This tree is native to Australia, where it mostly grows along the southern and eastern coast. It has become naturalized to Africa, Brazil, and New Zealand.
It usually grows to a height of about 65 feet (20 m), but its size and shape can be pretty variable.
Acacia melanoxylon (Australian blackwood), Leaves and flowers at MISC HQ Piiholo, Maui, Hawaii. photograph by Forest and Kim Starr, under creative commons license.
The bark can be dark grey to black in appearance. Acacia melanoxylon has phyllodes as opposed to leaves for foliage.
The phyllodes (modified petioles, or leaf stems) are grayish green and range from 1.5 to 6 inches (4 to 15 cm) in length.
Flowering Acacia melanoxylon Shrub by Forest and Kim Starr, CC.
In its native environment, Acacia melanoxylon has small blooms from July to December.
Gardener's HQ Guide to Growing Australian Blackwood
The growing of Acacia melanoxylon requires a lot of space due to its large size.
A large specimen can grow up to 80 feet (25 m) tall and have a sprawl as wide as 40 feet (12 m).
Because of the size of this tree, it should not be planted near sidewalks, pavement, or underground plumbing.
Full sun is required. This plant is not frost resistant so this tropical plant should only be grown in the warmer USDA zones, nine through eleven.
Australian Blackwood Seed Pods by Forest and Kim Starr, CC.
Well-drained soil with medium moisture tends to give the best results.
In proper conditions, the tree will grow quickly so be sure that it is directly planted somewhere that can accommodate a large tree instead of transplanting it at a later date.
Acacia melanoxylon is typically disease-free but may attract pesty weevils. It can help to attract avian pollinators to the area.
Australian Blackwood photograph close up of leaves and seedpods by Forest and Kim Starr; CC.
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Acacia melanoxylon Growing and Care Guide
- Scientific Name: Acacia melanoxylon.
- Common Names: Australian Blackwood, Black Wattle, Hickory.
- Growing Zone: USDA Zones: 9 to 11. Will grow in mild and coastal areas of Europe.
- Life Cycle / Plant Type: Evergreen. Shrub or Tree.
Plant Details
- Plant Height (Inches): can easily reach from 16 to 65 feet (5 to 20 m) or higher.
- Plant Spread (Inches): 12 to 40 feet (4 to 13 m).
- Time of Bloom: Spring.
- Flower Details: Fluffy. Racemes (2 to 4 inches (5 to 10 cm). Pale cream to brown, Yellow, or White. Fragrant.
- Leaf Foliage: Narrow lanceolate, Green.
- Fruit: Elongated. Flattened pod. Hairless. 1.25 to 6 inches (4 to 15 cm) in length.
- Bark: Dark Grey to black, scaly. Sapwood: White, Grey or Straw coloured.
- Growth Form: Spreading or horizontal, pyramidal or rounded.
Ideal Growing Conditions
- Best Light Conditions: Full sunlight, seedling will not grow in the shade.
- Rate of Growth: Quick.
- Suitable Soil Types: Deep. Rich and Fertile for best results. Clay, Loamy, Sandy. Acidic, Neutral, or slightly alkaline pH. Well drained.
- Soil Moisture: Dry to Moist (Medium Moisture likely gives best results).
Caring Conditions
- Care: Low maintenance.
- Propagation: Seed, requires fire. May spread from root suckers (same plant though).
- How to Prune: Minimal pruning required to help maintain shape.
- Pests: Weevil, termite, powder-post beetle.
- Diseases: Generally tolerant of disease.
Further Information
- Can attract: Parrots, Cockatoos, Pigeons, Butterflies, moths.
- Tolerant of: Fire.
- Best Garden Use: Winter interest, Areas requiring pest tolerance, Containers, Specimen, Large Garden, and Street Tree.
- Family: Fabaceae (beans).
- Native: Australia.
- Closely Related Species: Cootamundra wattle; Wild Senna; Fenugreek; Chinese Kidney Bean; California Redbud.
- Miscellaneous: Entices bird life to the garden, Non-native to North America. Attractive flowers/blooms. Wood has commercial value and is often used for Guitar making, tool handles, fence posts, and for light construction.
- Genus Detail: Acacia.
- Further Reading and References: Here and Here.
I hope that you enjoyed this guide on how to grow Acacia melanoxylon. You may also enjoy the following Fabaceae family growing guides: How to grow peas in your garden and Japanese Wisteria .
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