Disa bracteata. Photo: Leonie Smith By Terri Allen
Disa bracteata, formerly Monadenia bracteata, was found in January 2005 on regenerating heathland abutting the coastal reserve at the Wonthaggi Heathland.
The weed-orchid from South Africa was first found in Albany, WA in 1944, thought to be brought in sacking covering goods at the port. It spread northwards to Geraldton, eastwards to Esperance and to the edge of the wheat belt. It is now naturalised in WA, SA and Victoria.
Disa bracteata, formerly Monadenia bracteata, was found in January 2005 on regenerating heathland abutting the coastal reserve at the Wonthaggi Heathland.
The weed-orchid from South Africa was first found in Albany, WA in 1944, thought to be brought in sacking covering goods at the port. It spread northwards to Geraldton, eastwards to Esperance and to the edge of the wheat belt. It is now naturalised in WA, SA and Victoria.
This garden thug is spread on clothing, shoes, camping gear, vehicles and machinery. Each plant, self-pollinated, can produce up to 2.5 million dust-like seeds which, wind-borne for many kilometres (seed being viable for six years), is a real threat to the heathland. Seeds continue to mature even if the flower head is picked.
The orchid is a perennial up to 75 centimetres tall, rising on a fleshy stem from a rosette of many narrow leaves which are rich purple-red underneath. The rosettes appear in spring and the asparagus-like spikes bear from 10-50 flowers from September to November. These small green flowers have an elongated spur at the base of the dorsal sepal. They grow singly or in loose colonies, are generally found in open country and will grow in open competition with introduced grasses.
Disa bracteata has been seen in the Grampians and Latrobe Valley, on French Island and on private land near the Wonthaggi heathland. Our infestation may have begun with wind-borne seed from French Island or from seeds in fodder transported during the drought. Perhaps kangaroos carried the seed from private to public land.
We have had a campaign now for 11 years with hand-removal, digging up the plant, ensuring the tubers are removed. Recently two of us removed 1100 plants. Plants can be difficult to locate in heathy areas and among bracken. This year plants in full flower have been located on private land and in local reserves (Wonthaggi Heathland, the Wonthaggi Rifle Range wetlands and Baxters Wetlands.
If you find this plant, dig it up, double bag it and put it in the bin.
References
Hoffman & Brown: Orchids of SW Australia pp 319-321.
Blood: Environmental Weeds p173
Muyt: Bush Invaders of SE Australia
The orchid is a perennial up to 75 centimetres tall, rising on a fleshy stem from a rosette of many narrow leaves which are rich purple-red underneath. The rosettes appear in spring and the asparagus-like spikes bear from 10-50 flowers from September to November. These small green flowers have an elongated spur at the base of the dorsal sepal. They grow singly or in loose colonies, are generally found in open country and will grow in open competition with introduced grasses.
Disa bracteata has been seen in the Grampians and Latrobe Valley, on French Island and on private land near the Wonthaggi heathland. Our infestation may have begun with wind-borne seed from French Island or from seeds in fodder transported during the drought. Perhaps kangaroos carried the seed from private to public land.
We have had a campaign now for 11 years with hand-removal, digging up the plant, ensuring the tubers are removed. Recently two of us removed 1100 plants. Plants can be difficult to locate in heathy areas and among bracken. This year plants in full flower have been located on private land and in local reserves (Wonthaggi Heathland, the Wonthaggi Rifle Range wetlands and Baxters Wetlands.
If you find this plant, dig it up, double bag it and put it in the bin.
References
Hoffman & Brown: Orchids of SW Australia pp 319-321.
Blood: Environmental Weeds p173
Muyt: Bush Invaders of SE Australia