New 2020-21 weeds report published

Herbarium specimen of Euphorbia davidii, collected west of Caltowie from a localised but substantial population that was spreading into paddocks from the roadside. Photo: C.J. Brodie.

The State Herbarium of South Australia documents all known plant taxa (species, sub-species, varieties and forms) native and naturalised (weedy) in South Australia. These are listed in the Census of South Australian Plants, Algae and Fungi. All newly discovered State and regional records are added to the Census throughout the year. These records are based on preserved plant specimens, verified by a botanists and housed in the vaults of the State Herbarium.

For all new records of non-native plants, an annual report is produced by Weeds Botanist Chris Brodie and colleagues from the State Herbarium. The report includes the list of new weeds recorded for South Australia with locations, descriptions and photographs. Also documented are updates to taxa that have had a change in distribution, weed status or name. Other activities carried out by Weeds Botanist are also summarised, such as field trips or presentations to community groups.

The latest report is now available online:

Brodie, C.J. & Lang, P.J. (2021). Regional Landscape Surveillance for New Weed Threats Project, 2020-2021: Annual report on new plant naturalisations in South Australia. (2.2mb PDF)

Also available for download are last year’s 2019-20 report (16mb PDF), as well as the reports for 2018-19 (4.2mb PDF), 2017-18 (4.5mb PDF), 2016-17 (3.8mb PDF) and a compilation of all reports from 2010 to 2016 (3.7mb PDF).

These reports highlight to land managers, which non-native plant species have recently been found in South Australia and where. New records are listed as either “naturalised/established” (*) or “questionably naturalised/established” (?e).

At the end of June 2021, there were 5144 vascular plant taxa recognised in South Australia, of which 1618 are weeds, i.e. 31%. This year, 8 new weeds have been added to the Census; and over the last ten years, Chris Brodie’s weed surveys have discovered 244 new naturalised plants.

Naturalised plant taxa are those that have originally been introduced by humans to an area, deliberately or accidentally. They have self-propagated without aid, where they are not wanted, and are possibly spreading by natural means to new areas. Examples listed in the recent report, recorded as naturalised for the first time, are: Euphorbia davidii (Toothed Spurge) originally from the Americas, and Tradescantia crassula (Succulent Spiderwort) from the South America. These are examples of garden plants that have become weedy (see also a 1985 article by P.M. Kloot; 733kb PDF).

Questionably Naturalised taxa (i.e. possible new weeds) are introduced non-native plants that may be self-propagating without aid, but are not well established or lack data to classify them as naturalised. An example of this are Petunia ×atkinsiana (Garden Petunia) and Thunbergia alata (Black-Eyed Susan Vine). Australian species can also become weeds, such as Agonis flexuosa (Willow Myrtle) and Acacia penninervis var. penninervis (Hickory Wattle), both from other states.

Agonis flexuosa var. flexuosa and Petunia × atkinsiana, self-seeding in a fire-scar area on Kangaroo Island. Photo: C.J. Brodie.

The new state records Petunia ×atkinsiana and Agonis flexuosa were recorded for the first time for South Australia collected from Kangaroo Island, from within a fire scar from the 2019-20 bushfires. Also collected from KI, mostly from fire scars, were an additional 13 new regional weed records listed as naturalised or questionably naturalised for KI. This data is contained within the “Updates to weed distribution, weed status, and name changes” section of the report.

Any unknown weed or possible new state or regional weed records should be reported to Chris Brodie (0437 825 685, If you have permission from the landowner, you could press a plant, record collection data, and submit a preserved plant specimen for identification.

The pressed plant (or part of the plant) should consist of stems with leaves attached and preferably flowers and/or fruit. Collection data includes, plant location, habitat, frequency, height and width, colour and smell, and what the plant looks like when alive and growing. Images can help in identifying plants. Also include the date, your name and contact details.

Please use the pro-forma collection sheet (available as single page: 200kb PDF, or for double-sided printing: 220kb PDF) in pencil and submit it together with the pressed plant specimen.

Compiled by State Herbarium weeds botanist Chris Brodie.