(Also known as Mexican Devil)
Ageratina adenophora
Family: Asteraceae
Type of weed: Woody weed
Priority Weed Local Priority Weed. (See more weeds of the Local Priority Weed class.)
Flowering Months: January, September, October, November, December
Description
Crofton weed is a shrubby perennial with a woody rootstock and numerous upright branching stems. It usually grows 1–2 m high. A distinguishing feature is the purple-red stem.
The leaves are bright green, trowel-shaped, 50–75 mm long, 25–50 mm broad, with toothed edges. The leaf shape is a distinguishing feature.
It flowers profusely in spring and summer producing dense clusters of white sticky hairy flowers, 5–8 mm in diameter at the ends of the branches.
It produces millions of seeds.
Note:
It is poisonous to horses, causing Tallebudgera Horse Disease.
Dispersal
Seed is dispersed by wind and water over long distances and is also moved by vehicles, machinery, in clothing, soil and stock feed. It is also spread in dumped garden waste.
Impact on bushland
Crofton Weed spreads easily along creek lines and in other areas, forming dense stands, smothering native grasses and out-competing native shrubs.
Distribution
Lower Blue Mountains, Upper Blue Mountains. Lapstone to Wentworth Falls and Mt Tomah. More abundant in the Lower Mountains.
Alternative planting
Native plants
Alternative plantings to hold soils on creekbanks or stormwater drainage lines include ferns, rushes and sedges such as:
- Fishbone Water Fern (Blechnum nudum)
- Prickly Rasp Fern (Doodia aspera)
- Common Ground Fern (Calochlaena dubia)
- Broad Rush (Juncus planifolius)
- Common Rush (Juncus usitatus)
- Tall Sedge (Carex appressa)
- Daisy bushes (Olearia elliptica, O. myrsinoides)
- Waxflower (Phylotheca myiporoides)
In drier areas, plant Correa (Correa reflexa).
Council provides a tool, on its Mountain Landscapes website, to help you choose native alternative plantings. Choose your village, soil, vegetation community and the purpose of your planting, and the tool will give you suggestions.
There are native nurseries in several Blue Mountains villages, including Glenbrook, Lawson and Katoomba. Please also ask at your favourite local nursery.
Control
- Hand remove
- Remove flowers, fruit, pods or seeds
- Spray
- Cut and paint
Manual control
Hand remove
Grasp stem at ground level. Rock weed backwards and forwards to loosen roots, then pull out gently. Carefully tap the roots to dislodge attached soil. Replace disturbed soil and pat down.
Considerations
- Leave weeds so that roots do not make contact with soil; on a rock, for instance. A small amount of debris may be hung in a tree or removed from the site.
- Vary the position of your body to avoid fatigue when removing plants by hand over extended periods.
Remove seeds, pods or fruit
Gently remove any seeds, pods or fruit and carefully place in a bag.
Chemical control
Note: Herbicides that may be used for this weed include Fluroxypyr, Glyphosate, MCPA + Dicamba, Picloram, Triclopyr, Metsulfuron methyl.
Spraying
Please consult the Herbicide page of this website to help you decide whether to spray, how to do it safely and more.
Cut and paint
Useful for small to medium sized woody weeds up to 10 cm in diameter.
Make a horizontal cut as close to the ground as possible with secateurs or loppers, and immediately apply concentrated Glyphosate to the exposed stump surface. Do not allow the surface to get covered with soil.
Specific control tips for this weed
Most plants can be hand pulled easily, particularly when the soil is moist. Make sure all roots are removed. When hand removal is not possible, or there is a concern about destabilising creek banks, use the cut and paint method.
Do not leave removed plants on the ground as they can grow roots from the stems. Bag and dispose of all parts of the plant, preferably in a hot compost to kill the seeds and stems. Stems can be spread out to dry off the ground. Once dead, the material will decompose in place or may be composted.
It is best to treat the plant before it flowers to minimise the spread of seeds.
Low, dense patches can be sprayed with a selective herbicide that will not kill native grasses and shrubs. For more specific details on specific herbicides, please refer to the NSW Government WeedWise resource.
For key points on these techniques:
Local Priority Weed
Control measures:
- The plant should be fully and continuously suppressed and destroyed.
- Plants under 4 metres in height should be fully and continuously suppressed and destroyed.
- The spread of this plant should be adequately contained to prevent spread impacting on priority assets. Weed notices will only be issued for these weeds under special circumstances.
