Common Name: Goatweed

General Information

Ageratum conyzoides is a coarse annual plant with an erect stem and a strong, unpleasant smell. It can grow up to about 1 metre tall[].
The plant is often harvested from the wild for local use as a medicine; it is also sometimes grown as an ornamental plant[, , ].
The plant is a common weed in the tropics, though is much less likely to be a problem in the temperate zone[]. It can flower and produce fruit all year round; individual plants can produce 40,000 seeds and, in some areas, one-half of the seeds will germinate shortly after they are shed. Seeds are mainly spread by wind and water and will germinate under a wide range of conditions[].

Known Hazards

None known

Botanical References

Range

S. America - Argentina, Paraguay, Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, the Guyanas; C. America - Panama to Mexico; Caribbean.

Habitat

A common weed of cultivated ground, having spread from its native range to all areas of the Tropics within 20° of the Equator, to an altitude of 2,500 metres[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	1.00 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Ageratum conyzoides is not frost hardy, though it can be grown as a summer annual in many areas of the temperate zone[]
Succeeds in full sun in a sheltered position in any reasonably fertile moisture-retentive soil that does not dry out in the summer[]. Plants are reasonably tolerant of shade, though can be outcompeted by taller plants[]. Plant vigour and flowering periods are much reduced on dry soils[].
The plant is a common weed in the tropics[]. It can flower and produce fruit all year round; individual plants can produce 40,000 seeds and, in some areas, one-half of the seeds will germinate shortly after they are shed. Seeds are mainly spread by wind and water and will germinate under a wide range of conditions[].
The fresh plant is malodorous[].

Edible Uses

There are records that the fresh leaves have been eaten, combined with Abelmoschus esculentus[]. It only happens rarely and it is probably eaten mainly for its supposed medicinal benefits by nursing mothers who believe it helps to increase their milk flow[].

Medicinal

The whole plant is antiinflammatory and antiallergic[]. Antinematocidal, anti-inflammatory, anticoagulant, smooth muscle relaxant, haemostatic, analgesic, antifungal, antibacterial and hypothermic activities have been recorded[]. The plant also has an antidiarrhoeal effect[].
The plant contains between 0.7 - 2.0% essential oil, plus alkaloids and saponins[]. The essential oils contained in the plant have antibiotic properties[]. The plant is highly embryotoxic to Dysderus flacidis and acts on embryonic development at an early stage[].
The juice of the fresh plant, or an extract of the dried plant, is used in the treatment of allergic rhinitis and sinusitis[]. The juice of the fresh plant is also useful in treating post-partum uterine haemorrhage[].
The plant is used to treat constipation, infective hepatitis, eczema, epilepsy, fresh wounds, dizziness, diarrhoea, dysentery, sore eyes, fever, headaches, intestinal worms, filariasis, vomiting and nausea, wounds and cuts[].

The juice of the root is antilithic[, ]. A paste of the root, mixed with the bark of Schinus wallichii, is applied to set dislocated bones[].

The leaves are styptic[]. They are dried and applied as a powder to cuts, sores and the ruptures caused by leprosy[], The powder absorbs the moisture of the disease and forms a layer that is removed after 1 - 2 days[]. An effective cure for most cuts and sores, though it does not effect a complete cure for leprosy[]. The leaves are also used externally in the treatment of ague[, ].

The juice of the plant is used to treat cuts, wounds and bruises[].

A paste of the leaves is used as a poultice to remove thorns from the skin[]. A paste made of the leaves mixed with equal amounts of Bidens pilosa, Drymaria cordata, Galinsoga parviflora and the rhizome of Zingiber officinale is used to treat snakebites[].

The juice of the flowerheads is used externally to treat scabies, whilst a paste of them is used to treat rheumatism[]. A tea made from the flowerheads mixed with Ocimum tenuifolium is used to treat coughs and colds[].

Other Uses

The leaves and the flowers yield 0.2% essential oil with a powerful nauseating odour[]. The oil contains 5% eugenol, which has a pleasant odour[]. The oil from plants growing in Africa has an agreeable odour, consisting almost entirely of eugenol[].

A decoction of the fresh plant is used as a hair wash, leaving the hair soft, fragrant and dandruff free[].

Tannin extracts of goatweed showed insecticidal activity against flour beetles[].

Propagation

Seed - sow late winter or early spring in a warm greenhouse and only just cover the seed. Prick out the seedlings when large enough to handle and plant out after the last expected frosts[]. Seed can also be sown in situ in the spring and, for earlier blooms, it is possible to sow it in late summer or early autumn, though it will need to be overwintered in a warm greenhouse[].