Cookies on Plantwise Knowledge Bank

Like most websites we use cookies. This is to ensure that we give you the best experience possible.


Continuing to use means you agree to our use of cookies. If you would like to, you can learn more about the cookies we use.

Plantwise Knowledge Bank

Your search results

Plantwise Factsheets for Farmers

Ageratum conyzoides

Ageratum conyzoides

Recognize the problem

Family: Asteraceae (daisy family).

Common names: goatweed.

Kiswahili: matawana.

Annual broadleaved herb with green, purplish or reddish stems (0.3–1 (1.5) m tall). Stem branched and covered in short white hairs on young parts and nodes; shallow fibrous roots.

Leaves: Bright green, sparsely hairy, rough with prominent veins, triangular to egg-shaped (20–100 mm long and 5–50 mm wide) margins bluntly toothed with blunt or pointed tips, in opposite pairs; hairy petioles (5–75 mm); characteristic odour when crushed, smelling like a male goat.

Flowers: Blue to lavender, fluffy, sometimes with a white head in compact terminal cluster bearing 4–18 flowerheads (each 4–5mm across and 4–6 mm long), with slender, hardly exserted styles; slightly aromatic.

Fruits: Brown, small, dry and one-seeded.


Origin: Latin America.

Introduction: As ornamental.

Habitat: Humid tropical and subtropical regions; grows on both light and heavy soils; prefers most habitat but also grows in dry areas.

Spread: The seeds are mainly spread by wind and water, but are also readily dispersed on clothing or animal fur and machines.

Invades: Croplands, plantations, pasture,  grasslands, disturbed land, wasteland, urban open space, fallow land,  roadsides, railways, drainage ditches, riparian areas and forest edges/gaps.

Impacts: This weed reduces crop yields and is an important alternate host of a number of economically important crop pathogens and nematodes. It also readily displaces native plant species. It excludes native grasses and medicinally important plants, reduces native plant abundance and creates homogenous monospecific stands.  The species is an aggressive short-term colonizer of gaps in vegetation. It can become dominant following overgrazing. In Tigray, northern Ethiopia, accidental consumption of the seeds with sorghum was implicated in the cause of liver disease resulting in the deaths of 27 people and numerous livestock.

The recommendations in this factsheet are relevant to: All Countries

Authors: CABI. Edited by Abdul Kudra, Fridah Mgonja
Sokoine University of Agriculture, Box 3005, Morogoro
tel: +255(0) 754 632778 email:
©CAB International. Published under a CC-BY-SA 4.0 licence.

Plantwise Factsheets Library app

Get all of the factsheets and pest management decision guides from this website in an offline format via the Plantwise Factsheets Library app.