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Carolina Geranium

Carolina geranium (Geranium carolinianum) is a branching winter annual or biennial with long hairy stems that range from green to red in color. Leaves are hairy on both surfaces with various divided sections and bluntly toothed margins. The fibrous root system has a shallow taproot and usually has a maximum height under 12 inches. The flowers of Carolina geranium are found at the tips of stems and range in color from white to pink with 5 petals. The seeds have a distinctive elongated beak which gives the plant its nickname, cranesbill.

Carolina geranium is found throughout South Carolina and is commonly seen in areas of lawns, landscape beds, fields, and roadsides that receive minimal maintenance as well as areas with poor, dry soils.

The heavily dissected leaves of Carolina geranium (Geranium carolinianum) cause it to stand out from other plant species.

The heavily dissected leaves of Carolina geranium (Geranium carolinianum) cause it to stand out from other plant species.
Adam Gore, ©2019, Clemson Extension

Carolina geranium (Geranium carolinianum) stems range from red to green in color, and the plant has a shallow taproot.

Carolina geranium (Geranium carolinianum) stems range from red to green in color, and the plant has a shallow taproot.
Adam Gore, ©2019, Clemson Extension

Cultural Control

To reduce the presence of Carolina geranium in lawns, maintain a healthy stand of turfgrass with proper fertilization, irrigation, and mowing practices. Due to the shallow taproot, Carolina geranium can be easily pulled. For more information on turfgrass maintenance, refer to: HGIC 1216, Bermudagrass Yearly Maintenance Program; HGIC 1215, Centipedegrass Yearly Maintenance Program; HGIC 1217, Zoysiagrass Yearly Maintenance Program; HGIC 1218, St. Augustinegrass Yearly Maintenance Program; HGIC 1219, Tall Fescue Maintenance Calendar.

Chemical Control in Lawns

Before using any pesticide, be sure to read and follow all label directions. The label will specify any protective clothing, if necessary, which should be worn during handling and application.

Several 3-way herbicides containing 2,4-D, mecoprop (MCPP), and dicamba are available to homeowners for post-emergent control of Carolina geranium. These products may also contain carfentrazone or sulfentrazone. Applications can be made at any time throughout the life cycle, but for best control, applications should be made at the seedling or immature stage to prevent seed development.

These products can be used to spot treat Carolina geranium in tall fescue, bermudagrass, and zoysiagrass lawns. Areas containing centipedegrass or St. Augustinegrass may need reduced rates which will be stated on the product label. Injury to centipedegrass and St. Augustinegrass may occur if these products are applied during green-up, the transition period between dormancy and active growth in spring, or if applied during and excessively hot (>90F) and dry times during the summer.

Herbicide products containing atrazine can be used on centipedegrass and St. Augustinegrass for both pre- and post-emergent control. Rain or water within 2 or 3 days of application may decrease the effectiveness on existing weeds. However, for the control of weed seeds starting to germinate, rainfall or watering is necessary within 7-10 days of treatment, as atrazine products are absorbed by seedling roots. Do not apply atrazine in areas with a high water table or within two times the width of the drip line of desirable hardwood trees and shrubs.

The use of pre-emergent herbicides can prevent the germination and emergence of Carolina geranium. These products are commonly applied in fall and repeated 8-10 weeks later to prevent germination.

Note that broadleaf, post-emergent herbicides have the potential to harm desirable landscape plants. To avoid damage do not allow spray to contact desirable plants or their root zones. Avoid applications during windy conditions. Keep the sprayer nozzle close to the ground, adjust the nozzle tip for a coarse spray, and use a nozzle hood to prevent off-target damage. For more information on avoiding and identifying herbicide damage to landscape plants, please see HGIC 2349, Herbicide Damage to Landscape Plants.

Table 1. Examples of Post-emergent Herbicides for Control of Carolina Geranium in Turfgrass.

Product Brands Active Ingredient % Active Ingredient Labeled for Use on Listed Turfgrass Species
Bayer BioAdvanced Southern Weed Killer for Lawns Conc.; & RTS1 2,4-D
Mecoprop
Dicamba
7.59
1.83
0.84
Bermudagrass
Centipedegrass
St. Augustinegrass
Tall Fescue
Zoysiagrass
Lowered label rate for:
Centipedegrass
St. Augustinegrass
Bayer BioAdvanced Southern Weed Killer for Lawns RTU2 2,4-D
Mecoprop
Dicamba
0.311
0.075
0.034
Ferti-lome Weed Free Zone Conc.; & RTS1 2,4-D
Mecoprop
Dicamba
Carfentrazone
10.49
2.66
0.67
0.54
Gordon’s Trimec Ready to Spray Lawn Weed Killer RTS1 2,4-D
Mecoprop
Dicamba
5.56
1.34
0.62
Ortho Weed-B-Gon Weed Killer for Lawns Conc.; & RTS1 2,4-D
Mecoprop
Dicamba
8.658
2.127
0.371
Spectracide Weed Stop for Lawns Concentrate; & RTS1 2,4-D
Mecoprop
Dicamba
7.59
1.83
0.84
Spectracide Weed Stop for Lawns RTU2 2,4-D
Mecoprop
Dicamba
0.593
0.144
0.066
Bonide Weed Beater Plus RTS1 2,4-D
Quinclorac
Dicamba
6.42
2.13
0.60
Bermudagrass4
Ryegrass
Tall Fescue
Zoysiagrass
Bonide Weed Beater Plus RTU2 3 2,4-D
Quinclorac
Dicamba
0.313
0.104
0.029
Ortho Weed-B-Gon Plus Crabgrass Control Conc.; & RTS1 2,4-D
Quinclorac
Dicamba
6.42
2.13
0.60
Hi-Yield Atrazine Weed Killer Atrazine 4.00 Centipedegrass
St. Augustinegrass
Image for St. Augustine & Centipede with Atrazine Atrazine 4.00
Southern Ag Atrazine St Augustine Weed Killer Atrazine 4.00
1RTS= Ready to spray; hose-end spray bottle
2RTU= Ready to use; pre-mixed spray bottle
3Labeled for spot treatments
4Products containing quinclorac may temporarily yellow bermudagrass lawns.

Control in Landscape Beds

In landscape beds, a 2- to 3-inch mulch layer can suppress many weeds from germinating, including Carolina geranium. Mulch also greatly benefits landscape beds. For more information about the benefits of mulching, see HGIC 1604, Mulch. A pre-emergent herbicide containing dithiopyr (Dimension) or isoxaben (Gallery) can be used in landscape beds; however, the application of a pre-emergent may affect the rooting of landscape plants and subsequent plantings, so it important to read the label for its use around specific landscape plants.

Hand-pulling of Carolina geranium is effective due to its shallow taproot; however, be sure to remove the plant before it goes to seed to prevent further spread. If necessary, the use of an herbicide containing glyphosate is effective and will have less soil activity to affect nearby landscape plants, as compared to 3-way herbicides and atrazine.

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

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