Acacia melanoxylon
Acacia melanoxylon
Blackwood
Probably indigenous to the historical Black Forest.
A tall, straight tree with bark that is dark and becomes rough and furrowed with age. Its branches spread wide, giving the tree a rounded canopy. Young trees have smooth, thinner bark and more flexible branches. The root system is deep and extensive, typically forming a strong taproot with lateral roots, providing stability and efficient water uptake.
Height: 18 m (±12 m)
Width: 10 m (±5 m)
Reaches maturity: 8.5 yrs (±1.5 yr)
Lifespan: 75 yrs (±25 yrs)
Leaves:
Leaves of acacias are actually flattened leaf-like stems called phyllodes which allow the plant to reduce water loss and survive in dry environments. Just like leaves, phyllodes produce food for the plant. The phyllodes of this species are dark green on top and slightly paler underneath. They have a smooth and leathery texture and can be up to 14 cm long and 3 cm wide. They grow alternately along the stem.
Flowers:
Flowers are fluffy, round and small, usually about 5 mm across. They are creamy-yellow and appear in clusters of 3 to 5 along the branches. Each flower is made up of many tiny stamens, which give a fuzzy appearance. The flowers are lightly fragrant and attract insects like bees, which help with pollination. The flowers are important for the tree’s reproduction, as they eventually turn into fruit.
Fruit:
The fruit are long, thin, curved pods which turn brown as they mature. The pods are typically 5–10 cm long. Inside are shiny, hard seeds, about 4–6 mm in length, each surrounded by a small, fleshy covering called an aril. The pods split open when they dry out, releasing the seeds, which can then grow into new trees. These seeds are often scattered by wind or animals, which eat the fleshy arils. The pods hang on the tree for several months, maturing in late summer to early autumn. They have a papery texture and can remain attached to the tree for some time after releasing their seeds.
Growing Environments:
This species grows well in a variety of environments, from moist forests to drier, inland areas. It thrives in well-drained soils and can tolerate both acidic and alkaline soil-types. While it prefers areas with regular rainfall, it is surprisingly drought-tolerant once established. It can grow in full sun or partial shade. In wetter areas, it grows faster and reaches greater heights, but it adapts to drier soils by growing slower and developing a deeper root system. It is commonly found along riverbanks, in woodlands, and even on the edges of rainforests. Despite its tolerance for dry conditions, young trees benefit from occasional watering in droughts.
Role in Ecosystems:
This species plays an important role in ecosystems by providing food and shelter for many animals. Birds nest in its branches, and insects such as bees and butterflies are attracted to its flowers. It is a source of nectar for the Two-spotted Line-blue and Wattle Blue butterflies, and a food plant for their caterpillars. The seeds are eaten by birds and small mammals, which also help in seed dispersal. The tree improves soil fertility by fixing nitrogen through a symbiotic relationship with bacteria in its roots. This ability to enrich the soil benefits other plants growing nearby, contributing to healthier ecosystems. Additionally, the dense foliage offers protection for wildlife, while the fallen leaves decompose and add organic matter to the soil. It is a pioneer species, meaning it is one of the first trees to grow in disturbed or degraded areas, helping to rebuild ecosystems after environmental damage.
Uses in Gardening and Revegetation :
This species grows quickly and provides good shade. It can be used as a windbreak or hedge in large gardens, helping to protect other plants. Its dense canopy provides habitat for birds and insects. Its deep roots help prevent erosion, and its ability to grow in a range of soils makes it valuable for land rehabilitation. It its roots are disturbed, by humans or animals such as bandicoots or rabbits, it can propagate itself through root suckers.
Propagation:
From late summer to early autumn collect mature seed pods that have dried. Place pods in a paper bag and leave for 1 to 2 weeks or until pods begin to split. Open dried pods to dislodge seeds. Sow seeds from spring through summer. Place seeds in a mug and pour on just-boiled water. This process helps break the seed coat, allowing water to penetrate and initiate germination. Optionally, add some smoke water. Soak for 12 hours or overnight. Sow immediately in a well-draining seed-raising mix and keep moist but not waterlogged. Germination usually takes 3 to 4 weeks. Seed viability should be high. While seed propagation is more common, cuttings can be taken from young, healthy trees in late spring or summer. Dip the cuttings in rooting hormone and plant them in moist, sandy soil.
Seasonal Tasks:
Early Spring
No tasks needed in this season
Late Spring
Early Summer
Late Summer
Autumn
Winter
No tasks needed in this season
