COTTON BUSH CONTROL is best achieved during Spring & Summer
The time to control cotton bush is NOW! As the weather warms, we are seeing lots of cotton bush plants popping up around our area. October marks the beginning of both the active growing season and the best time for effective control of this highly invasive, declared pest weed. Cotton bush aggressively out-competes native and agricultural plant species, posing a major threat to food systems and the natural environment. It invades pastures and can form dense thickets many hectares in size. It is toxic to livestock but is rarely eaten. This weed also infests riparian areas where it competes with native plants.
Control Requirements: Under the Biosecurity and Agriculture Management Act 2007 (BAM Act), Narrow leaf cotton bush (Gomphocarpus fruticosus) falls under the C3 management category, which requires landholders to control this plant to minimise its spread. This means that landholders with cotton bush on their property have a responsibility to actively control this plant to stop it from spreading to neighbouring properties; best practice guidance is to remove all cotton bush within 100 metres of each property boundary. Studies conducted on cotton bush 1m and 2m tall have found that seeds, on average, dispersed approximately 50m from the parent plant by wind; as such, the best practice guidance is to establish a 100m buffer from all property boundary lines to minimise seed spread to neighbouring properties
Effective control of this plant can be achieved with both herbicide and manual control options.
- If pods are present, it is essential to remove and properly dispose of pods to prevent seed dispersal
- remove ALL pods from the plant’s stem (the pods are filled with seeds).
- place removed pods in a black plastic bag in the sun for 3 weeks so solarisation of the seeds can take place; this “cooks” the seeds, essentially killing them
- For Small Infestations (1-100 plants) with pods absent or removed:
- pull plant from the ground (may require tree popper, if deep rooted, which can be loaned from LBG).
- once plant is pulled, it recommended that plant is burnt, though removing the plant and leaving it in situ providing seed pods are removed, as this is efficient on a broad scale.
- For Large Infestations (>100 plants):
- Herbicide control is recommended for large infestations
- Pods Present- for control with herbicide or manually, it is best practice to remove pods first and solarise them as above. With chemical control, pods can be left, however there is a risk of pods bursting prior to the parent plant being killed.
- Chemical control for cotton bush is commonly done with glyphosate; however, other herbicides can be used. Find out more at: www.agric.wa.gov.au/herbicides/narrow-leaf-cotton-bush-control
Control equipment available for loan from LBG:
- “Tree poppers”: for manually pulling out cotton bush plants
- Herbicide Spray Equipment: – depending on the size of infestation to be controlled, landholders may want to borrow hand-held or backpack spray units or for use for control of large infestations, you can borrow LBG’s trailer-mounted, 400 litre capacity, retractable reel sprayer
Why report cotton bush infestations?
When following up on reports of cotton bush infestations, we find that landholders and land managers are often not aware of the infestation on their property or are not aware of their responsibility to manage the spread of this declared weed. Upon discussion, most landholders do responsibly respond and take action to address control needs.
When cotton bush infestations are reported to LBG, our team will:
- validate report with a visual sighting and map its location
- contact the applicable landholder/manager to bring to their attention the cotton bush infestation and related control responsibilities, guidance and available assistance
- if, after several attempts, we are unable to make contact with the landholder/manager or they do not address infestation control requirements, the infestation location is reported to DPIRD for potential control compliance follow-up
Read more Cotton bush at: https://www.agric.wa.gov.au/declared-plants/narrow-leaf-cotton-bush-what-you-should-know