[Geelong Advertiser, Page: 14, Tuesday, 17 November 2009] ONE would imagine that the discovery of another orchid in the Anglesea heathlands, widely acknowledged as one of the most important areas for native plants in southeastern Australia, would be welcomed. There is already a list of more than 100 native orchids known in the area, many of them rare plants. In fact there are three that can not be found anywhere else in the world. But the discovery of a dozen plants of the South African weed orchid Disa bracteata has raised concerns. If this invasive species gains a foothold here, it may be to the detriment of the heathiand’s natural assets.
The plants were found growing on the side of Fraser St in Anglesea, at a place often used as a car-park by visitors to the heathiands. They were identified by Margaret MacDonald, who has a wonderful knowledge of local flora, particularly orchids.
Weeds are never welcome, and enormous amounts of money are spent on the control of agricultural and environmental pest plants each year. Like many of the worst plants, these weeds have come from South Africa’s Cape Province.
It may not become an agricultural pest but it will compete with native orchids, grasses and other small plants for space, nutrients and water, all scarce commo ditie s in the heathlands.
Disa was first found in south-west Western Australia in 1944, the seeds perhaps windborne or accidentally brought in on shipping containers.
It established quickly and now occupies thousands of square kilometres of that worldfamous wildflower area It reached South Australia in 1988, possibly carried from the west by misguided orchid enthusiasts, and is now spreading at a rate of about 10km annually.
Three years later, plants were found near Bacchus Marsh and it has now been recorded at 10 Victorian sites.
The South African weed orchid is selfpollinating, produces thousands of minute seeds that can be windborne over kilometres.
The plant produces several large tubers from which the leaves and flowers arise in spring.
The robust stems holding up to 60 flowers usually reach about JUcm in height, and the yellow-and-brown flowers are compressed along the stem. In this way, it somewhat resembles the native onion and leek orchids.
The Anglesea plants were carefully excavated to remove both tubers and flowers before being burnt, and visitors to the area are urged to report any other suspect plants to Parks Victoria or DSE.
Wildlife information and questions can be sent to ppescottoptusnet.com.au