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Ageratum conyzoides
Tropical Whiteweed
Billygoat Weed
Not native to Florida
This herbaceous annual is more prevalent in south Florida, but can now be found in various locations in the peninsula as far north as Clay County, plus in Leon and Gadsden Counties. Native to Mexico, Central America and the Caribbean, plus most of South America.
The erect, branching stems are covered with soft hairs and grow to about 1m (~3 ft.) tall. Leaves are opposite and up to 10cm (4 in.) long and 5cm (2 in.) wide with hairy petioles up to 7.6cm (3 in.) long. Leaves are lanceolate to broadly ovate with coarsely serrated margins. Leaf surfaces are slightly hairy and rough and give off a strong rancid odor when crushed. Flowers are less than 6mm (1/4 in.) across and can be white or various shades of blue, pink or violet. Ageratum conyzoides plants tend to have from 30 to 75 flowers in tight heads. The pappus is made up of bristles, a feature that helps differentiate this plant from blue mistflower (Conoclinium coelestinum) which does not have a pappus of bristles.
Ageratum conyzoides is a member of the Asteraceae - Aster family.
Atlas of Florida Vascular Plants (Institute for Systemic Botany) profile for this species
USDA Plant Profile for this species
Date record last modified: Dec 16, 2022
