Captions: Acacia baileyana (Cootamundra Wattle) growing at Jindalee National Park; The bipinnate leaves and flowers of Cootamundra Wattle. Photos: J. Lynch
Cootamundra Wattle (Acacia baileyana) first caught my attention when I moved to Canberra six years ago. Its bright yellow clusters of ball-shaped flowers produce a stunning burst of colour during the cold winter months, and it retains its attractive grey-green, fern-like, bipinnate leaves throughout its life. Growing to between three to 10 metres in height, it thrives in cool, higher rainfall areas and is very adaptable, hardy and fast-growing. No wonder it is such a popular garden plant.
Cootamundra Wattle is so ubiquitous in the open spaces of Canberra, I initially thought it must have been native to this region. However, I soon discovered that it is a pest plant in the ACT and that many volunteers spend countless hours removing it from our bushland reserves. It is also classified as an environmental weed in many other parts of Australia (Western Australia, South Australia, Queensland, New South Wales and Victoria) as well as overseas in New Zealand and South Africa.
For such a hardy and prolific plant which grows so well in a wide range of climates and soils, Cootamundra Wattle intriguingly had a very restricted natural distribution at the time of European settlement. It only grew in the vicinity of Cootamundra, hence the common name, between Stockinbingal, Temora, Cootamundra and Bethungra (a distance of only about 50 km, east to west). Despite this, it is not considered to be at risk in the wild. Unsurprisingly, it is the floral emblem of Cootamundra and is on the logos of many local businesses, organisations and the Shire Council.
A.baileyana was first described by Baron von Mueller in 1888. He named it after the Queensland botanist Frederick Manson Bailey who collected the type specimen from a cultivated plant in Bowen Park, Brisbane in 1876. Bailey was a prolific botanist who made valuable contributions to the characterisation of the flora of Queensland and was Colonial Botanist of Queensland for many years.
In 1935, the botanist Mr I.V. Newman undertook a seven month study on the status and natural range of Cootamundra Wattle, going some way towards trying to explain its contradictory character. He reported that across its native range the species was limited to elevated sites near the crest of the divide, at an altitude of between 400 and 800 metres, on outcrops of Silurian sedimentary rock associated with patches of granites and porphyries (igneous rocks with large crystals such as quartz), with an average annual rainfall of between 18 and 23 inches, and sheltered from the south and west by the high ground of the range. The only other similar area in NSW was a much smaller area just to the north.
These facts led him to hypothesise that ‘it seems possible, therefore, that it is a relict of a species which may have flourished widely before physiographic changes initiated a losing battle between it and the environment’; and later: ‘It is either an old species living in a restricted habitat or it is a new species that did not spread far before the coming of settlement’. Perhaps we will never really know.
What we do know is that it is now a weed. Waltraud Pix, the Coordinator of the Friends of Mt Majura Parkcare group for 10 years until 2013, actively coordinates the restoration of endangered Yellow-box Red Gum Grassy Woodland at a site in North Watson every Friday morning, where one of the main activities is eradicating Cootamundra Wattles by either the ‘cut and paint’ or ‘frilling’ methods. I asked her recently why they are such a problem. ‘The mature trees produce large quantities of seeds every year, which are spread by water and birds over large distances and remain viable in the soil for decades,’ Waltraud said. ‘It easily invades our natural areas, especially after any disturbance, and competes with native shrubs, small trees and ground flora. They can form dense thickets excluding light and preventing the regeneration of indigenous native species.’
‘Cootamundra Wattle also frequently hybridizes with the local closely related Silver Wattle (A. dealbata), which could potentially threaten the long term survival of Silver Wattle in this area,’ Waltraud added. ‘Therefore I suggest to anyone with Cootamundra Wattle in their gardens, especially if they live near bushland, to replace it with a non-invasive species sold from bush friendly nurseries.’
The best place to view Cootamundra Wattle in its natural habitat is Jindalee National Park, which covers an area of 1,076 hectares and supports isolated stands of near threatened and vulnerable open forests dominated by Red Ironbark, Grey Box, Black Cypress Pine, Red Stringybark and Scribbly Gum. It was only recently declared in 2011 after many years as a state forest. The wattles are most plentiful in the, smaller south-eastern section of the park on the right hand side of Berthong Road, approximately 14 kilometres north of Cootamundra. Drive in through the gate, park in a suitable spot and just take a walk around. Specimens growing in the dense regrowth forest tend to be somewhat spindly whereas in open sites they are much more robust and profuse, with many large thickets to be found. Unfortunately, the park suffers from the effects of illegal dumping, vehicle access and fire wood collection.
A few years back a Cootamundra Wattle self-seeded in my back garden, which left me in a bit of a quandary. At first I was loath to remove it, but as much as I enjoyed its splendour, I eventually bit the bullet. Now there are a few Silver Wattles growing in its place, which are just as splendid.
Written by Jo Lynch. Originally printed in ‘Fronds’, the newsletter of the Friends of the Australian National Botanic Garden Number 77, August 2014