The lightwood tree has a greyish brown bark and evergreen oval, sickle-shaped leaves (which are not true leaves but actually flattened stems known as phyllodes) that sometimes appear purple based on soil condition. The growth cycle brings flowers, leaves and finally seed pods. The showy flowers arrive in summer, cream-colored to pale yellow, formed in a burst of round spiky flower heads that are strongly fragrant. The flowers are followed by a twisted cylindrical seed pod that has an unusual texture and appearance, a bit like a large pea pod, that starts out green and slowly turns reddish brown. The tree has a long history of being used for many practical purposes by the Aboriginal people of Australia, including for string, rope, medicine, and flour made from the seeds. It’s also used to make “fish poison” (a substance traditionally used by the Aboriginal people to make fish easier to catch). The leaves may also be used to make yellow or brown dye. The tree was first formally noticed by visiting English botanists in 1842, but as a well-known native tree it was in significant use well before that. Although the lightwood tree is familiar and well-loved in Australia for its showy blossoms and easy care, it can be quite invasive in non-native environments. It is vigorous, long-lived and fast-growing, which adds to its undesirability in areas where it has invaded. It is currently considered an invasive alien species in South Africa, where it was originally planted as a planation crop. Now the tree invades farmlands and other open areas and spreads rapidly there, with little to be done other than cutting them down as fast as they pop up.
Soil
Lightwood grows in a variety of soil conditions, and is very tolerant of poor soil that is full of sand or clay. This soil tolerance makes it very hardy and useful for bank and erosion stabilization, and it forms suckers readily when the roots are injured.
Light
This tree loves bright sun and grows easily wherever there is ample light for it to proliferate. But even in a sunny spot, first you’ll want to consider whether you have room for this tree: its mature height is between 20 and 50 feet tall.
Water
Adequate water is important for the lightwood tree, but it doesn’t do well if it is overwatered. Regular watering during times of drought is particularly important to prevent the formation of toxic compounds in the seedpods when the plant is dehydrated.
Temperature and Humidity
The lightwood tree is tolerant of both heat and drought, and also fairly frost tolerant for an Australian native tree. It’s also quite tolerant of air pollution such as car exhaust so it makes a good choice for planting along roadsides or near parking lots, and also makes a good urban or street tree because of its easy adaptation to many conditions.
