Urena lobata

Common Name: Caesar's weed

Family: Malvaceae

Common Synonyms: Urena trilobata

USDA Hardiness Zone: 9b-11

Growth Habit: Subshrub

Origin: Tropical Asia and India

FISC Category: 1

FDACS Listed Noxious Weed: No

Introduction Date: Earliest Florida specimen available vouchered in 1877

IFAS Assessment:

• North: INVASIVE
• Central: INVASIVE
• South: INVASIVE

Description

Large annual growing to about 3 m high. Leaves are 4 to 8 cm long, with shallow palmate lobes, and pubescent. The flowers are pink, grow in clusters, and have a tube of united stamens. Fruits are covered in hooked bristles and break into five segments at maturity, easily attaching to animals and clothing.

Habitat

Widespread in peninsular Florida. Readily invades hammocks, disturbed sites, or infrequently burned natural areas.

Comments

Cattle aid the spread of this species by carrying the seeds and disturbing the soil.

Control Methods

• Manual: NA
• Chemical: Imazapyr 0.5-1% with 6 to 9 month retreatment is most effective. Glyphosate (3-5%), Triclopyr (2-3%), Imazapic (0.5-1.0%) are also effective (IFAS).
• Biological: NA

Control Notes

Shade will help to deter growth and limit seedling establishment. Mulches or other ground cover will also prevent seed germination.

References

Langeland, K.A., H.M. Cherry, C.M. McCormick, K.C. Burks. 2008. Identification and Biology of Non-Native Plants in Florida's Natural Areas-Second Edition. IFAS Publication SP 257. University of Florida, Gainesville, Florida.

IFAS. 2017. Caesar's Weed, Urena lobata. http://plants.ifas.ufl.edu/plant-directory/urena-lobata/. Accessed June 13, 2017.

Wunderlin, Richard P., and Bruce F. Hansen. Guide to the Vascular Plants of Florida. 3rd ed. Gainesville, FL: U of Florida, 2011.