Crofton Weed

(Also known as Mexican Devil)

Ageratina adenophora

Family: Asteraceae

Type of weed:

Flowering Months: , , , ,

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

, . 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

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 info

For key points on these techniques: