Acacia auriculiformis Seeds | Earleaf Acacia
LATIN NAME: Acacia auriculiformis
COMMON NAME: Earleaf Acacia
Plant Profile
Acacia auriculiformis is a fast, short-lived tree with a leaf that is not a leaf. The foliage is made of phyllodes, flattened leaf stalks that function as leaves, curved and about fifteen centimetres long, with several longitudinal veins. The true leaves appear only on the seedling, and they are divided and fern-like, which is how the plant is recognised as a young plant.
The species is native to the monsoonal north of Australia and to New Guinea, and it has been planted throughout the tropics for fuel, for pulp and for shade. The flowers are in yellow spikes, and the pods curl into a tight spiral when they dry, holding black seed with an orange aril. The tree reaches fifteen metres and often leans or forks, and it is not long-lived, seldom past forty years.
Science & Biotechnology
The phyllode is an adaptation to drought. A flattened stem has fewer stomata than a leaf of the same area, and it is stiffer, so it holds its position in wind and heat. The plant also fixes nitrogen through rhizobia, and it grows on sand, on mine spoil and on degraded pasture where little else will establish.
The species is a heavy seed producer and a vigorous resprouter. It suckers from the roots after fire or cutting, and the seed is carried by ants, which take the aril and leave the seed in their nests. Those traits make it a useful pioneer and a serious weed: in Florida and in parts of South-East Asia it forms dense stands that shade out native vegetation, and it is listed as invasive in several jurisdictions.
Uses & Benefits
The wood is used for fuel, for charcoal and for pulp, and it is one of the main species in social forestry plantations in Asia. The bark yields tannin, and the tree is planted for shade in plantations and for stabilising sand and spoil.
In Australia the seed and the aril are eaten by birds, and the plant is used in land restoration on degraded sites. The wood is also used for small poles and for fencing, and the flowers are a source of nectar for bees. It is not a timber tree of high value, since the stem is often crooked.
Growing from Seed
Seed needs treatment: pour boiling water over it and leave it to soak overnight, or nick the coat. Sow at 25 to 30 degrees, and germination is in one to three weeks. The seedling is fast and can be planted out at three months.
The plant grows on sand, clay, acid and saline soils, and it tolerates drought and short flooding. It needs full sun and no care. The caution is its spread: it seeds heavily, suckers after cutting and can colonise open ground within a few years, so do not plant it near bushland or where its spread cannot be controlled.
Our Take
A fast pioneer for fuel and for poor ground, and an invasive tree where it is planted outside its range. Use it where it can be harvested.
Related Reading
Continue exploring with these related plants: