CaesarweedCaesarweedUrena lobata Urena lobata (L.) Malvaceae(L.) Malvaceae

Biology Biology • Native to central/south AmericaNative to central/south America

• Accidentally introduced (unknown) Accidentally introduced (unknown)

• Tolerant to salinity and droughtTolerant to salinity and drought

• Mallow plant family – similar to cotton, Mallow plant family – similar to cotton, sida, and hibiscussida, and hibiscus

• Annual species in central Florida, Annual species in central Florida, short-lived perennial in southshort-lived perennial in south

Distribution & ImpactsDistribution & Impacts

• Found in central and south FloridaFound in central and south Florida

• Associated with disturbed sites, pastures, Associated with disturbed sites, pastures, roadsides and perennial crop plantationsroadsides and perennial crop plantations

• Competes with forage species and Competes with forage species and desirable native plantsdesirable native plants

Caesarweed Distribution in FloridaCaesarweed Distribution in Florida

IdentificationIdentification

Mature PlantMature Plant• Erect Erect

herbaceous herbaceous shrub, 7-10 feet shrub, 7-10 feet talltall

• Freely Freely branching, branching, bushy bushy appearanceappearance

LeavesLeaves• Leaves are arranged Leaves are arranged

alternatelyalternately

• 2 to 4 inches long2 to 4 inches long

• Palmately lobedPalmately lobed

• Pubescent with Pubescent with stellate hairsstellate hairs

Flowers and FruitFlowers and Fruit• Flowers borne in Flowers borne in

axillary clustersaxillary clusters• Pinkish-violetPinkish-violet• Fruit are Fruit are

pubescent with pubescent with hooked bristles hooked bristles or barbsor barbs

• Cling to clothing Cling to clothing and furand fur

ManagementManagementPreventativePreventative

CulturalCultural

MechanicalMechanical

BiologicalBiological

ChemicalChemical

PreventativePreventative1.1. Remove existing plants before seeds Remove existing plants before seeds

are producedare produced

2.2. Rouge plants from fencerows, Rouge plants from fencerows, ditchbanks – prevent seed spread into ditchbanks – prevent seed spread into clean areasclean areas

3.3. Avoid treatments or cattle grazing Avoid treatments or cattle grazing during fruit set – spread seedduring fruit set – spread seed

CulturalCultural1.1. Shade will deter growth and limit Shade will deter growth and limit

seedling establishmentseedling establishment

2.2. Mulches or a good ground cover will Mulches or a good ground cover will prevent seed germination and prevent seed germination and seedling developmentseedling development

BiologicalBiological1.1. There are no known biological control There are no known biological control

agents available for caesarweed agents available for caesarweed management in Florida or the management in Florida or the southeastern U.S.southeastern U.S.

MechanicalMechanical1.1. Hand pull plants, small infestationsHand pull plants, small infestations

2.2. Mowing or cutting is effective, but Mowing or cutting is effective, but larger plants may resproutlarger plants may resprout

3.3. Cultivation or other tillage is very Cultivation or other tillage is very effective, but not a viable option in effective, but not a viable option in many areasmany areas

ChemicalChemical1.1. Limited research in this areaLimited research in this area

2.2. Over-the-top applications of triclopyr Over-the-top applications of triclopyr or other pasture herbicides at 1 to 2% or other pasture herbicides at 1 to 2% solution plus 0.25% surfactant solution plus 0.25% surfactant

3.3. Apply in spring, prior to flowering and Apply in spring, prior to flowering and fruit developmentfruit development

Useful LinksUseful Links• Floridata Homepage:

http://www.floridata.com/main_fr.cfm?state=Welcome&viewsrc=welcome.htm

• University of Florida Center for Aquatic and Invasive Plants: http://aquat1.ifas.ufl.edu/welcome.html

• The Plant Conservation Alliance's Alien Plant Working Group. Weeds Gone Wild: Alien Plant Invaders of Natural Areas: http://www.nps.gov/plants/alien/index.htm

Useful LinksUseful Links• Pacific Island Ecosystems at Risk (PIER).

Plant Threats to Pacific Ecosystems: http://www.hear.org/pier/threats.htm

• USDA Natural Resources Conservation Service. Plants Database: http://plants.usda.gov

Literature CitedLiterature CitedLangeland, K.A. and K. Craddock Burks. Langeland, K.A. and K. Craddock Burks. 1998. Identification and Biology of Non-1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. Native Plants in Florida's Natural Areas. IFAS Publication SP 257. University of IFAS Publication SP 257. University of Florida, Gainesville. 165 ppFlorida, Gainesville. 165 pp