SafePlants

Ageratum (Tropical Whiteweed)

Ageratum, also known as whiteweed in the USA, is a genus comprising 40 to 60 species of flowering annuals and perennials. These plants thrive in tropical and warm temperate climates.

Considerations for Pets

• This plant is often found as a weed in gardens.

Taxonomy and Nomenclature

• Scientific Name: Ageratum conyzoides L.
• Genus: Ageratum L. (whiteweed, ageratum)
• Family: Asteraceae (also known as Compositae)
• Tribe: Asteraceae
• Common Names: Tropical whiteweed, goatweed, chick weed, floss flower, flossflower, invading ageratum, tropic ageratum, white weed, winter weed, billy goat weed, blue top, blue weed, bokkruid, Indringer-ageratum.
• Synonyms: A conycoides, A obtusifolium, Cacalia mentrasto

Distribution and Habitat

• Native to tropical North and Latin America.
• Found in the United States in Hawaii, California, and the southeastern states from Mississippi to Florida.
• Also found in Suriname and Maui.
• Habitats include disturbed areas.

Ecological Role

• Considered a common weed.
• Mentioned as an escapee from cultivation in parts of the United States.
• Identified as an invasive species and a minor problem species in some regions.

Morphological Characteristics

• Annual herbaceous plant.
• Grows up to 3 feet in height.
• Features little white flowers and opposite leaves.
• Leaves may have a gland-dotted lower surface.

Interactions with Other Organisms

• Predatory mites (Amblyseius newsami) have been found in citrus orchards where Ageratum conyzoides is present.

Further Information

• Dave's Garden
• Discover Life
• Garden Guides
• US Geological Survey
• iStock
• Alamy