Acacia oswaldii - the old wattle

Plants

10 Dec

Wattles are generally described as early colonisers; short-lived, fast-growing, quick to establish after fire, that sort of thing. However, there are a few arid-zone wattles which are long-lived and very slow growing, Acacia oswaldii is one of those.

In 2012, I set up a photo-point to monitor the growth of some seedlings I had found. Four times a year I took photos, then twice, then once a year, and now I just have a look when I’m nearby. The seedlings are still less than 40 cm high. Makes you wonder how old this whopper would be!?

Our giant Acacia oswaldii (growing right down to the ground with not much sign of the “Umbrella Wattle” shape) — Our giant *Acacia oswaldii* (growing right down to the ground with not much sign of the “Umbrella Wattle” shape)

Acacia oswaldii has many common names depending on where you live, in the Mallee it’s often called “Umbrella Wattle” because its growth form is like an umbrella. But we think it is only like this when the grazing pressure is too high, when grazing pressure is low it grows right down to the ground.

It has a wide but sparse distribution across arid and semi-arid mainland states, although in Victoria it is considered threatened (listed under the Flora and Fauna Guarantee Act). Because it is slow-growing, the seedlings remain susceptible to browsing, particularly from rabbits, for many, many years. Research suggests grazing pressure can be enough to prevent seedlings from establishing at all.

We always collect some seed to include in our revegetation. It is the last Mallee wattle to flower, starting in about late November with pale yellow flowers. The seed pods are huge, woody and give rise to one of the common names - Ram’s Horn wattle. It seems to only produce a good seed crop every other year but it is a pleasure to pick and clean the seed - large glossy black seeds with a colorful aril, very pretty!