The arid and semi-arid plants of NSW demonstrate some extraordinary adaptations to climate, soils and microclimate!
With El Nino on its way as well as long term climate warming, it’s good to understand which plants might cope with the tough, hot and dry conditions.
Here are some of the plants seen on a recent 3200 km trip to western NSW and north west Victoria, including White Cliffs (the white opal town), Broken Hill, Menindee Lakes, Mungo and Mildura.
Note: Happy to be corrected if I have plant names wrong!
What’s an arid plant?
Australia is considered to be 70% arid/semi-arid, with arid defined as receiving under 250ml of rain pa and semi-arid being 250 – 350mm pa. Rain is not necessarily seasonal but occurs over longer term cycles characterised by a boom/bust cycle of droughts and floods and hot dry summers and cold winters.
The so-called ‘deserts’ of NSW include grasslands, shrublands, woodlands and swamplands. They are dominated by chenopod and acacia shrublands, with species that are drought and salt tolerant such as Sclerolaena (burrs), Atriplex (salt bush), Maireana (bluebushes, cottonbush), Chenopodium and Rhagodia genera, as well as the acacias (https://www.anbg.gov.au/photo/vegetation/chenopod-samphire-forb.html).
The flora of these regions show some wonderful survival and reproduction adaptations. These are both physical and behavioural and include modified leaves and stems for storing water and preventing water loss and deep penetrating roots with water storage capability and ability to re-sprout after fires.
Here are some of the plants you might see in these regions, many with broader horticultural potential.
Wilcannia and White Cliffs
Near Wilcannia, on the side of the road, I found Eremophila duttonii, as well as Flindersia maculosa (Leopard Wood).
E. duttonii looks like a definite candidate for the garden with its lovely red/yellow flowers.
The Leopardwood tree has beautiful mottled bark and though a straggly tree, I do wonder if it would work in a raised bed.
Dissocarpus paradoxus (Cannonball), Hard-headed Saltbush, looks attractive but that fluffy fruit breaks down and 5 nasty spines appear, perfect for sticking into feet or animals. Maybe we’ll leave that where it is!
The Maireana was beautiful with its soft delicate flowers and succulent looking leaves. There are 57 Maireana species in Australia, all endemic. The fruits superficially resemble flowers, being small flat discs, which are often red or yellow in colour.
Maireana has made its way into cultivation as a highly ornamental but hardy shrub. Adelaide Botanic Gardens says this of Maireana brevifolia (Cotton Bush, Small Leaf Bluebush): A highly ornamental but hardy foliage plant. Plant singly for contrast or as a feature in wider verges or grouped as an informal hedge, screen or wind-break. Tolerates moderate coastal exposure and calcareous soils. Requires well-drained soils.
The plains around White Cliffs are masses of grey foliage low shrubs (saltbushes, bluebushes, copperburrs) and a few acacia trees.
Wandering amongst the diggings of White Cliffs (famous for its white opals), I saw Ptilotus sp. (possibly P. spathulatus). Ptilotus contains about 120 species, with most coming from the Pilbara. They are herbs or small shrubs often with pink flowers that hang down like a tail, hence their common name of pussycat, lambs or fox ‘tails’. One of the Aboriginal names that has stuck is ‘Mulla Mullaa’. They are endemic to Australia. The ones seen in White Cliffs had creamy coloured flowers.
A number of the Asteraceae family, such as Gnephosis sp. and Olearia sp. were also flowering. Of course, given the diggings, it was a surprise that anything could survive, yet I found quite a few species popping up around the mine shafts.
Onto Broken Hill
A highlight of Broken Hill was the Living Desert State Park. Nestled amongst the Barrier Ranges, it is a 2400 ha reserve which includes the Living Desert Flora and Fauna Sanctuary. The area includes the Sculpture Park, which is also worth a look-see!
Flora included the restricted range Eucalyptus gillii, with a common name of Curly mallee or Silver mallee. It is an attractive small tree and grows naturally in sandy soil and may be worth a place in the garden if you have room. The lovely yellow flowers and attractive buds make a lovely addition. (https://resources.austplants.com.au/plant/eucalyptus-gillii/).
Other plants on show included Eremophila serrulata (Green Fuchsia), Olearia pimeliodes, Ptilotus obovatus and Solanum sturtianum. This last one is probably not a good candidate for the garden, given its poisonous berries, but it does make an attractive shrub in this environment.
Another interesting plant was Acacia tetragonophylla (Dead Finish) which is a rather straggly shrub growing 2 – 3m with each flower on a single stalk.
Its common name is believed to have two causes i.e. ‘when the cows start eating the Dead Finish bush, everything else has died’ or ‘in a bad drought, this is the last bush to die’. The Aboriginal name for the plant, from the Warlpiri language is ‘Kurara’. The Arrernte name is ‘Arlketyerre’.
The Arrernte people use the sharp spiky leaves to treat warts. The bark from roots is also steeped in water to make an antiseptic solution for treating sores. First Nations people also gather the seeds grinding them for cakes, although they are also known to eat the seeds raw. (https://ausemade.com.au/flora-fauna/flora/acacia/dead-finish-acacia-tetragonophylla/).
This image, looking west from Broken Hill, brought home to me the extraordinary emptiness, and beauty of our Australian landscape.
Originally a series of natural depressions on the Darling River, the lakes were modified during the mid-20th century to make use of the water for conservation. Agreements were struck by the NSW Government with the Australian, Victorian and South Australian governments that water could be shared to meet downstream water needs when the lake volume reached certain levels.
Many people will recall the major fish kills of 2018 and 2019, where it is believed over a million fish died. The causes are not fully known but are thought to be a function of the low water flows, over-distribution of water and high temperatures around that time leading to blue-green algal blooms. Further fish kills occurred in 2023, with the incident being investigated by the EPA.
At the time of our visit, Menindee Lakes were full. The landscape was a magnificent sight, and the birds were extraordinary in numbers. Aerial shots showed the lakes and landscape although the vegetation was a little distant to identify!
As the sun set, the birds went wild. Large flocks flew overhead and settled on the inundated trees, as I attempted to capture the stunning landscape! And we did see some saltbush on the way.
Mungo National Park
Lake Mungo dried up over 14,000 years ago. It is home to the earliest modern human remains found in Australia, with Mungo Man and Mungo Lady dating back 40,000 years. It is also a rich fossil area.
We were rained out of Mungo, so apart from a brief opportunity to explore the Walls of China, there was no chance to do much botanising. The park on the way in and the Walls of China fit our normal view of ‘desert’ – being an area of red sand dunes, very sparsely vegetated.
The drive out again was a bit hairy – 5 minutes notice to LEAVE! And then escorted out – apparently just 5mls of rain creates a quagmire of red slush, that takes a week to dry out.
Mildura, the Australian Inland Botanic Garden
I really enjoyed this garden with many of the arid and semi-arid plants on display.
The concept of a semi-arid botanic garden was the brainchild of three scientists from CSIRO who brought it to the attention of Mildura Council back in 1983.
Plantings showcase both native and exotic species from semi-arid regions.
There was a magnificent field of Swainsona formosa, Sturt’s Desert pea, with its blood-red flowers.
I was surprised to learn that there are about 85 species of Swainsona globally with all but one endemic to Australia. Most are prostrate. Some produce a phytotoxin that causes disease in cattle when ingested, with the sickness referred to as ‘peastruck’.
Here are some other species seen in the garden:
- Rhagodia spinescens – attractive silvery foliage, good for a hedge, many soil types tolerated and purportedly fire retardant
- Maireana sp – silvery or succulent leaves, attractive bracts
- Exocarpus aphyllus – unique looking plant with no obvious leaves, grows as a shrub or small tree with tiny red berries
- Eremophila sp – well known to many of us and needing no further introduction!
- Ptilotus exaltatus – stunning small plant, but I treat it as an annual
- Eucalyptus oleosa – a mallee which purportedly can be burned many times as the lignotuber will keep sprouting. Local Aboriginal people advised that water could be extracted from the unearthed roots of the tree.
- Citrus australasica x native lime – deep red fruits with pink tinged flesh on the inside. A cross between the Finger lime (Citrus australasica) and the Burmese Rangpur lime (Citrus x limonia), making the fruit more juicy throughout instead of being contained only in the pearls, as in the finger lime.
The rest of the garden was a fascinating collection of arid and semi-arid plants, many of which were labelled.
This garden is well worth a visit and the opportunity to wander paths and explore the many arid and semi-arid plants – potential for east coast gardens over the next 20 or so years.
Australian Government, Department of Climate Change, Energy, the Environment and Water, Outback Australia – the rangelands, https://www.dcceew.gov.au/environment/land/rangelands
M. Cunningham, W. E. Mulham, P. L. Milthorpe and J. H. Leigh, 2011, Plants of Western NSW, CSIRO Publishing, ebook
Ecosystem guides, a field guide to the planet by Damon Ramsey, Plants, https://www.ecosystem-guides.com/plants-of-Australian-desert-shrublands.html
Gardening with Angus, https://www.gardeningwithangus.com.au/native-lime-citrus-hybrid-red-centre-lime/
NSW government, Office of Environment and Heritage, Bioregions of NSW, Broken Hill Complex, https://www.environment.nsw.gov.au/-/media/OEH/Corporate-Site/Documents/Animals-and-plants/Bioregions/bioregions-broken-hill-complex.pdf
NSW National Parks and Wildlife Service, Desert and arid shrubland environments, https://www.nationalparks.nsw.gov.au/environments/deserts-and-arid-shrubland-environments
NSW National Parks and Wildlife Service, Mungo National Park, https://blog.nationalparks.nsw.gov.au/mungo-national-park-the-land-frozen-in-time/?_ga=2.176399009.546750062.1688699760-476872297.1663887453
M.E. Westbrooke, M.K.C. Kerr and J. Leversha, 2001, The vegetation of Kinchega National Park, western New South Wales, NSW Government, Royal Botanic Gardens Sydney, https://www.rbgsyd.nsw.gov.au/getmedia/b701cb84-c7a7-461d-b95f-4c054b58bdfd/Volume-7(1)-2001-Cun7Wes001-1-26-(1).pdf.aspx