Acacia melanoxylon (Black Acacia) - A very quick-growing attractive and upright evergreen tree to 40 to 50 feet tall or much more with about a 20 to 30 foot width and, in maturity, an oval to pyramidal shaped crown. It has rough dark gray bark with vertical fissures and mid-green leaf-like flattened stems, called "phyllodes", that are 2 to 5 inches long by about an inch wide, with one margin straight and the other slightly curved and with 3 to 5 prominent longitudinal veins. These leaves are shiny light-green at first and age to a dark flat-green color. Small creamy white flowers are in a small ball-like cluster with protruding stamens from late winter into spring and are followed by thin curling seed pods that hang in brownish sheaves.
Plant in full sun to light shade in a soil with fairly good drainage. Hardy to 15-20 degrees F and tolerant of heat, alkalinity and coastal conditions. This durable tree that is often planted for its quick growth, screening and erosion control in groups or as a solitary specimen.
While attractive and quite useful for various purposes, its aggressive roots can lift sidewalks, damage foundations and plumbing and, together with leaf, seed pod and branch litter and its propensity to sucker and reseed, it is not ideal for street plantings. It was highly recommended for street tree plantings in California prior to the 1940s, so it is still fairly commonly seen. In Southern California it is not seen as an invasive plant, but in the bay area it has been documented as a plant that reseeds, so its use there is not recommended.
Black Acacia comes from coastal areas of southeastern Australia where it grows from sea level to 3,500 feet in solitary stands in cool temperate rainforests or as an understory to larger Eucalyptus. The name Acacia comes either from the Greek word 'akazo' meaning "to sharpen" or from the Egyptian word 'akakia', a name given to the Egyptian Thorn, Acacia arabica. The specific epithet comes from the Greek words 'melas' meaning "black" and 'xylon' meaning "wood" for the dark wood of this species, which also gives it its common name Black Acacia. It is also called Blackwood Acacia as its hard, dark wood makes high-quality lumber and it is used for cabinetry and other decorative work. It was introduced from Australia into England in 1819 and was one of the first Australian plants offered for sale in California. William Walker first listed its availability in his 1858 Golden Gate Nursery catalog (together with 78 other species of Acacia). We have grown this tree since 1980.
Information about Acacia melanoxylon displayed on this page is based on our research about it conducted in our library and gathered from reliable online sources. We include observations made of this plant as it grows in our nursery gardens and in other gardens that we have visited, as well as how the crops have performed in containers in our own nursery field. We will also incorporate comments that we receive from others about this plant when we feel it adds information and particularly welcome hearing from anyone who has any additional cultural recommendations that would aid others in growing it.