Locations within which Ageratina adenophora is naturalised include Australia, southern Europe, Africa, Asia, New Zealand, south-western USA and many. Photo: Bart Wursten Ballantyne Park, Harare. Ageratina adenophora. Photo: Bart Wursten Ballantyne Park, Harare. Ageratina adenophora. Photo: Bart Wursten. A. adenophora has proved to be a very aggressive invasive species in some parts of the world, notably Australia, where it forced some farmers.
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Click on images to enlarge. Crofton weedcat weedcatweed, croftonweed, hemp agrimony, Mexican devil, aheratina agrimony, sticky eupatorium, sticky snakeroot, white thoroughwort.
Ageratina adenophora is invasive in parts of Kenya including around Lake Naivasha A. The editors are not aware of records of the presence of A. This species is a weed of roadsides, railways, pastures, fence-lines, disturbed sites, waste areas and riparian zones banks of watercourses in subtropical and warmer temperate regions. It is also commonly found in urban open spaces, open woodlands, forest margins and rainforest clearings.
A long-lived perennial herbaceous plant or small soft-stemmed shrub usually growing m tall, but occasionally reaching 3 m in height. It produces numerous upright erect stems from a woody rootstock. The branched stems are densely covered in sticky glandular hairs when young and may be green, reddish or purplish in colour.
They become slightly woody and turn brownish-green or brown in colour when mature. Its roots are yellowish in colour and give off a distinct carrot-like smell when xdenophora or damaged. The leaves are oppositely arranged along the stems and are borne on stalks petioles cm long.
The broad leaf blades cm long and cm wide are trowel-shaped, diamond-shaped rhomboidor triangular with bluntly or sharply toothed crenate or serrate margins. These leaves have sharply pointed tips acute apices and are mostly hairless glabrousbut their stalks are often covered in sticky hairs they are glandular pubescent.
The small white flower-heads capitula consist of several tiny flowers tubular florets surrounded by two rows of greenish bracts an involucre mm long. These flower-heads mm across are borne in large numbers and arranged in clusters at the tips of the branches in terminal corymbose inflorescences. The tiny tubular florets mm long are white and contain both male and female flower parts they are bisexual.
The ‘seeds’ achenes are slender, reddish-brown or blackish-brown in colour, and adenophpra curved. These ‘seeds’ mm long and 0. However, they are topped with a ring pappus of numerous whitish hairs mm longwhich are readily shed. Ageratina adenophora reproduces by seeds which are easily dispersed by wind and float on water. They addenophora also be spread in by animals and vehicles and can contaminate agricultural produce.
Ageratina adenophora is quite similar to Chromolaena odorata Chromolaena and Gymnocoronis spilanthoides Senegal adenopyora plant. These species can be distinguished by the following differences:.
Ageratum houstonianum blue billygoat weedAgeratum conyzoides subsp. When in flower, they can be easily distinguished by their bluish, purplish or pinkish-coloured flower-heads.
Ageratina adenophora has been moved around the world as an ornamental but it is now more known for its negative impacts. Ageratina adenophora is regarded as an environmental weed in many parts of the world. It is also very invasive in South Africa and Zimbabwe. In Queensland and New South Wales, this species colonises forest margins, stream banks and disturbed areas, preferring shaded wetter areas but also growing in open sunny sites.
Factsheet – Ageratina adenophora (Crofton Weed)
It also thrives in damp areas such as wetland margins, drainage lines, gullies and in clearings in wetter forests. It grows in large dense clumps and will eventually out-compete all other plants in an area, choking out native vegetation and forming a monoculture. It prefers wetter pastures e. It is also poisonous to livestock, being particularly toxic to horses.
In fact, this species is the cause of an acute pulmonary disease in horses which is known as “Tallebudgera horse disease” in Queensland and “Numinbah horse sickness” in New South Wales. This condition can be fatal if enough of the weed is consumed over a long period. The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species.
Some components of an integrated management approach are introduced below.
The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing early detection and rapid response.
Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before adenophofa infestations are tackled.
Consistent follow-up work is required for sustainable management. Ageratina adenophora can be manually controlled by cutting with a machete pangafollowed by ripping out the plant or ploughing, then sowing desirable pasture species. Small infestations can be dug out and exposing the roots.
Ageraatina, like so many flowering plants, it can set down a significant seed bank in the soil so that other mechanical control can become continuous. The fact that this plant often grows in swamps and difficult to access areas like riverbanks makes control difficult but herbicides have been used to control this plant.
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When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt acenophora an expert. A tephritid stem galler, Procecidochares utilis has been introduced to control A.
In Hawai’i the fungus Entyloma compositarum Basidiomycetes: Ustilaginales is considered effective. A combination of fungal infestation of plants during wet periods and the impact of the stem galler has resulted in other plants growing in A. Not listed adeniphora a noxious weed by any state or government authorities in Kenya, Tanzania or Uganda. Global Compendium of Weeds. Hawaiian Ecosystems at Risk Project. Alien weeds and invasive plants.
A complete guide to declared weeds and invaders in South Africa. Agave sisalana Perrine, Asparagaceae: Federal Noxious Weed Disseminules of the U. Click on images to enlarge comparison of crofton weed Ageratina adenophhoraleft, and mistflower Ageratina ripariaright Photo: Sheldon Navie seedling Photo: Sheldon Navie infestation Photo: Sheldon Navie close-up of the flower-heads, each with numerous tiny tubular flowers Photo: Sheldon Navie the small white flower-heads are borne in dense clusters Photo: Sheldon Navie the branched flower clusters at the tips of the stems Photo: Sheldon Navie habit in flower Photo: Sheldon Navie close-up of the relatively broad and almost triangular leaves Photo: