Crofton Weed

ageratina adenophora

Crofton Weed (Ageratina adenophora), also known as Mexican devil, is a highly resilient, fast-growing perennial shrub native to Mexico. Despite its delicate appearance with soft clusters of white flowers, this plant is recognized globally as an extremely aggressive invasive species. It thrives in disturbed soils, damp hillsides, forest edges, and riverbanks across Australia, South Africa, Asia, and the Pacific. Its exceptional ability to outcompete native flora makes it a major concern for conservationists and agriculturalists alike. What makes Crofton Weed particularly formidable is its ecological strategy; it actively alters the surrounding soil chemistry to suppress competing vegetation, establishing dense monocultures. It is also toxic to livestock, particularly horses, which can develop chronic, sometimes fatal respiratory conditions from grazing on its leaves. This botanical invader stands as a prominent example of natural adaptability and is a primary target for biological control programs around the world.

Habitat: Typically found in damp, disturbed environments such as agricultural pastures, roadsides, forest margins, and riparian zones.

Appearance

This upright perennial herb typically grows between 100 and 200 centimeters tall, forming dense, multi-stemmed clumps with a woody base. Its upright stems have a distinctive reddish-purple hue and are covered in sticky, glandular hairs that release a subtle scent when touched. The leaves are oppositely arranged along the branches, shaped like a trowel or a diamond with sharply serrated margins and a rich green color. During its blooming period, Crofton Weed produces flat-topped clusters of small, fluffy white flower heads at the branch tips, each looking like a tiny, petal-less pom-pom.

KingdomPlantaePhylumTracheophytaClassMagnoliopsidaOrderAsteralesFamilyAsteraceaeGenusAgeratina

Crofton Weed

Interesting facts

Consumption of Crofton weed is highly toxic to horses, leading to a chronic and often fatal pulmonary disease known as 'Tenterfield disease'.

It was originally introduced to many countries outside its native range as an ornamental garden plant due to its pretty white flowers.

Its scientific name 'adenophora' translates to 'gland-bearing', referring to the sticky, hair-like glands covering its stems and leaves.

Special abilities

Releases toxic chemical compounds from its roots and decomposing leaves to inhibit the germination and growth of competing native plant species.

Produces up to 100,000 tiny, lightweight seeds per plant that are equipped with a hair-like pappus for efficient wind and water dispersal.

Capable of sprouting new shoots rapidly from its woody root crown or broken stem nodes after mechanical damage or fires.

Measurements & details

Length: 100-200 cm
Lifespan: 3-10 years

Diet & Feeding

As a photoautotrophic plant, it synthesizes its own food using sunlight, water, and carbon dioxide through photosynthesis, while absorbing essential minerals from the soil.

Primary Foods

Sunlight
Carbon dioxide
Water
Soil nutrients

Ecological connections

eaten by

Crofton Weed Gall Fly

Procecidochares utilis

The larvae of this introduced biological control fly burrow into the stems of the weed, forming galls that restrict growth.

parasite

Crofton Weed Black Smut Fungus

Entyloma ageratinae

This pathogenic fungus infects the leaves of the weed, causing leaf spots and severe defoliation as a biocontrol agent.

mutualism

Western Honey Bee

Apis mellifera

Visits the small white flower clusters to collect nectar and pollen, accidentally assisting in pollination.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Crofton Weed?

The easiest way to identify Crofton Weed is to use the Snappit nature identifier app.

How long is Crofton Weed?

100-200 cm

How long does Crofton Weed live?

3-10 years

What does Crofton Weed eat?

As a photoautotrophic plant, it synthesizes its own food using sunlight, water, and carbon dioxide through photosynthesis, while absorbing essential minerals from the soil.

Where is Crofton Weed usually found?

Typically found in damp, disturbed environments such as agricultural pastures, roadsides, forest margins, and riparian zones.