Thread Iris (Moraea setifolia), a minute South African perennial naturalised across dry interior regions of southern Australia.
In Australia, the plant was first collected in parkland near Adelaide in 1881, with multiple collections over the ensuing twenty years from fields, roadsides and other sites to the immediate north and east of the city. It became common enough in SA to be confused with and gain the common name ‘Nutgrass’, a name which would have typically refered to Cyperus, sedges with, you know, sedgy reproductive parts.
In 1905, Thread Iris was recorded inside the Victorian border, opposite the SA town of Frances, and in Melbourne within Albert Park. A further record was made in 1910 at Burnley.
Too small of flower to have been of great interest to ornamental growers (although some presumably gave it a try), it seems likely that the initial introductions and spread of Thread Iris came in contaminated grass seed, hay or silage. The collections record suggests that the plant only became widespread throughout Victoria’s interior from the 1940s, presumably under the influence of heavy tread mechanical farm and road maintenance equipment. Within Melbourne, the species has been recorded principally on the western fringes, although scattered records exist across the outer north and at bayside sites.
The photographed plants are abundant in mown cemetery lawns at Truganina (adjacent to an MNES grassland), and on various roadsides in the surrounding area. Surprisingly, the species was not listed in the most recent (November 2015) vegetation survey at the cemetery, perhaps because the tiny plant’s flowering period had concluded prior to the survey.
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Search for information about Moraea setifolia in the Flora of Victoria
View information and occurrences of Moraea setifolia on the Atlas of Living Australia
October 25, 2021 at 6:52 PM
To my dismay this plant, thread iris (Moraea setifolia) has taken over a long bed of beautiful plants in our front garden in Sandringham, 100 metres from Beach Park. Also, this plant has entwined itself into a bed of kangaroo paw. I cannot distinguish the foliage of the thread iris from that of the kangaroo paw, so cannot remove the unwanted thread iris. In my opinion this plant should be removed from the environment whenever possible.
November 21, 2021 at 4:48 PM
Shirley, if it is thread iris in your front garden, you should be able to differentiate it even when not in flower by the single grass-like leaf. I suspect you have probably been beset by another weedy Iris in Iridaceae with a more tufted or fan-like foliage, like Blue Pigroot (Sisyrinchium micranthum), a widespread weed of southern Victoria which we desperately need to write up on this website.