Priority Weeds
Weeds are a major threat to remnant vegetation and the fauna that rely on locally native plants for survival. Weed invasion is responsible for the loss of many species of plants and animals from areas across Australia, including the Mornington Peninsula. Weeds also impact on waterways, stock, crops, tourism.
Weeds can be classified as Environmental, Noxious, a Weed of National Significance, and sometimes can be all three. Below is a list of the Mornington Peninsula Landcare Networks Top 12 weeds, however there are many that could have been placed on this list. For a more comprehensive list, please see the Mornington Peninsula Shire’s GUIDE TO NOXIOUS & ENVIRONMENTAL WEEDS OF THE MORNINGTON PENINSULA
Landcare’s Top 12 Environmental Weeds
1. South African Weed Orchid
Disa bracteata
An emerging threat to the Mornington Peninsula’s native wildflower populations, this highly invasive environmental weed produces millions of dust-like seeds allowing it to spread easily and form dense colonies. If we allow this plant to invade unchecked the consequences could be devastating.
South African Weed Orchid is the only invasive non-native orchid in Victoria. First found in the 1940s, South African Orchid has established populations across the state. Most plants are found in
moderately disturbed areas. However, it does invade bushland, where it can compete with and exclude smaller native plants such as lilies, grasses and orchids.
Identification
South African Onion Weed is erect, fleshy and can reach up to 50cm high. The green leaves form a rosette and have purple undersides. It grows above-ground annually from tubers. Each plant has up to 60 tiny flowers along a dense spike. It flowers mainly during Sep–Dec. The small flowers have a red-brown hood and and a yellow labellum (larger bottom petal) that protrudes forward like a tongue. The black, minute and dust-like seeds are contained within the fruit.
Lookalikes
South African Weed Orchid may be confused with similar native species, Microtis spp. and Leek-orchids (spp.), however native orchids can be distinguished as they have only a single leaf emerging at the base of the stem.
Treatment
If you suspect that you have found a South African Weed Orchid infestation:
- Do not disturb – there is a high risk of spread
- Contact Mornington Peninsula Shire on 1300 850 60 for advice regarding identification, its management and how to reduce its spread.
- Connect with your neighbours and local Landcare Groups to undertake control, share what management methods have been successful, and work together to manage the spread collaboratively.
For small infestations, manually dig up and remove all parts of the plant, including the tuber, leaves and flowers before seed set. Bag all material securely to prevent the fine dust-like seed from spreading and dispose in general waste (not green waste). Large infestations need to be chemically controlled.