- Widespread. Asia, Africa. North, South and Central America, Caribbean, Oceania. In most Pacific islands.
- Aggressive, invasive plant, fast-growing, capable of forming dense thickets. Able to grow in variety of soil types in forests, pastures, waste ground, swamps, waterways, roadsides, coastal dunes, plantations. Seeds easily spread.
- Erect, long-lived shrub, up to 2 m tall. Young stems green, with star-shaped hairs; older, woody. Leaves, alternate along the stems, up to 10 cm long. Lower leaves of variable shapes, uppermost smaller; all with toothed margins, pointed tips, and star-shaped hairs. Flowers, pink, 1.5-2 cm, single, with five reddish-pink petals, numerous stamens and branched style. Fruit, splits into five, 1-seeded segments, with hairs and spines.
- Spread: burrs, by animals; clothing; water; soil, produce, vehicles.
- Biosecurity: high risk of introductions on clothing. Noxious weed in Cuba, Fiji, USA.
- Biocontrol: little known.
- Cultural control: hand weeding; vehicle hygiene.
- Chemical control: in Australia: MCPA. In Fiji, glyphosate.
Pacific Pests, Pathogens and Weeds - Online edition
Pacific Pests, Pathogens, Weeds & Pesticides
Urena burr (468)
Click/tap on images to enlarge
Summary
Common Name
Urena burr; it is also known as caesar weed, Chinese burr, Indian mallow, or Congo jute. CABI prefers caesar weed.
Scientific Name
Urena lobata. Another species, Urena sinuata, is considered to be the same as Urena lobata by some taxonomists. A member of the Malvaceae.
AUTHORS Grahame Jackson, Aradhana Deesh & Mani Mua
Adapted from Urena burr (Urena lobata) (2018) Weeds of SE Qld and Northern NSW. Lucidcentral. (https://www.lucidcentral.org/editors-pick-animal-and-plant-identification-keys/key-to-weeds-of-se-qld-and-northern-nsw); and additional information from CABI (2019) Urena lobata (caesar weed). Invasive Species Compendium. (https://www.cabi.org/isc/datasheet/55771). Photo 4 Gerald McCormak, Cook Islands Biodiversity & Natural Heritage. (http://cookislands.bishopmuseum.org).
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland, in association with the Pacific Community and Koronivia Research Station, Ministry of Agriculture, Fiji.
