Recognize the problem
Common names: goatweed.
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.
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.
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.
Brown, small, dry and one-seeded.
Humid tropical and subtropical regions; grows on both light and heavy soils;
prefers most habitat but also grows in dry areas.
The seeds are mainly spread by wind and water, but are also readily dispersed
on clothing or animal fur and machines.
Croplands, plantations, pasture, grasslands,
disturbed land, wasteland, urban open space, fallow land, roadsides, railways, drainage ditches,
riparian areas and forest edges/gaps.
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.