Blackwood acacia, Acacia melanoxylon, happens to be one of my least favorite trees, but it does happen to be rather interesting. Mature trees have no leaves. Really. I don’t mean that they defoliate through winter and refoliate in spring. Only juvenile growth has bipinnately compound leaves. As growth matures, leaves are smaller, and are outfitted with distinctively winged petioles. As growth progresses, the winged petioles, known as ‘phyllodes’, become more prominent, and lack vestigial leaves. Therefore, once mature trees outgrow their juvenile growth, no leaves remain.
I dislike blackwood acacia because it is an invasive exotic species, like Acacia dealbata, but not as invasive. Mature trees sucker profusely from roots to form groves of several straight and vertical trunks. Where they are not a problem, groves of mature trees are rather handsome, but do not last long before they start to deteriorate. Foliar liter has an herbicidal effect that inhibits weed growth, but also inhibits the growth of desirable plants. It also produces an objectionable aroma.
1. Juvenile leaves are bipinnately compound, like those of Acacia dealbata.
2. Leaves become more diminutive with distinctively distended petioles as growth matures.
3. Adult foliage is comprised exclusively of phyllodes, without leaves. The phyllodes function and look just like simple leaves.
4. Blackwood acacia flowers are not much to look at. Even in full bloom, they are grungy yellowish white.
5. At least the bark is handsome.
6. The best blackwood acacia is a dead blackwood acacia.
This is the link for Six on Saturday, for anyone else who would like to participate: