What is Ground Ivy?
Ground ivy is a non-native perennial herb. It was introduced into North America by settlers as early as 1672. Since then, ground ivy has escaped cultivation and spread to a variety of native plant communities throughout the United States.
Herb or Weed?
Ground ivy is also known as gill-over-the ground, cat's foot, and creeping Charlie. This mint-family relative with delicate bluish-violet to lavender flowers is considered by most to be a noxious lawn weed that is hard to eradicate. Ground ivy hugs the ground, escaping mowing and aggressively spreading by above-ground runners (stolons) that can grow to 7 feet in length. Ground ivy creeps along the soil surface and puts down roots at each node (where the leaf attaches to the stem). These multiple attachment points make hand weeding very difficult. For this reason, some describe ground ivy as "plant Velcro."
Pretty But Pesky
Ground ivy is a perennial evergreen plant that is a member of the family Lamiaceae. Leaves are opposite, heart-shaped, 0.8-1.2 in. (2-3 cm) wide, petiolate, and scalloped. When the leaves are crushed, a pleasant aromatic minty smell is released. If you roll the stems between your fingers, you can detect the squareness of the stems, which is a way to distinguish it from common mallow (Malva neglecta). Plants can reach a height of 1 foot (0.3 m).
Ground ivy is one of the earliest plants to flower in the spring and blooms from March to July, dates critical to remember if you want to control this weed. Ground ivy has lavender-blue tubular, flowers that appear in the axils of the leaves. The flowers are 0.4 in. (0.9 cm) long and come in clusters of two or more.
Ground ivy is common in moist areas, disturbed sites, low woods, lawns, and along roadsides. It tolerates sunny as well as shady spots. While not listed as an invasive plant in Pennsylvania, many turf experts consider this one of the most difficult weeds to control in the lawn because it spreads by seeds and stolons. It can form dense mats and take over entire areas of the lawn.
Eradication
Cultural Control
Because ground ivy prefers shady locations, planting shade-tolerant grasses may deter its spread.
Mechanical Control
Often the first attempt at removing ground ivy is just to pull it out. Make sure you get all of the rootlets or the plant will grow back. Try this method after a fresh rain when the soil is looser. Most ground ivy infestations are large and would frustrate the best hand-weeder.
Biological Control
There are no known biological controls.
Chemical Control
There are reports that a good old-fashioned laundry product--20-Mule Team Borax--controls ground ivy. Researchers at Iowa State University applied 20 or 30 ounces of Borax, mixed in 1 gallon of water, to the plant for control, concluding that the ground ivy was sensitive to the boron in the Borax and was injured to the point of dysfunction. This treatment is not effective in all areas due to variations in the chemical makeup of soil.
Herbicides
Ground ivy is considered a broadleaf weed. Hence, application of a broadleaf weed herbicide may help eradicate the invasion. Application timing is critical and multiple applications are needed for up to 2-3 years.
Apply a postemergent broadleaf herbicide twice a year: in the spring when the plant is flowering (March-May) and late fall (Sept-Nov) when the plant is actively growing. Do not apply in the summer. Try a combination herbicide (Surge, Trimec Classic, Speed Zone) that contains these three chemicals:
- 2, 4-D (2,4-dichlorophenoxyacetic acid)
- Mecoprop or MCPP (2-[2methyl-4 chlorophenosy] propionic acid)
- Dicamba (3,6-dichloro-o-anisic acid)
Another option is to use products that contain triclopyr (Confront, Chaser, Battleship, Momentum, Weed-B-Gon purple label) a chemical that has activity on weeds that are traditionally hard to control. Due to complementary modes of action, combinations of tri-clopyr and 2, 4-D can be very effective.
Check the label and appropriateness for home use, as some combination herbicides are only sold to professionals. Always choose your herbicide wisely and apply strictly according to the label directions.
Only use in or near a vegetable garden if the label specifies this use. To be safe, do not apply when crops are present to minimize pesticide residue on edible crops.
Plan to reseed or spot-repair the grass to encourage rapid fill-in soon after the turf has been treated, since new weeds will quickly reestablish in the areas left open by recently-killed weeds.
One of the best ways to prevent infestations of ground ivy are to mow high (3") and fertilize adequately (2 lbs. nitrogen per 1,000 sq. ft.) to keep a strong, tight turf. Sometimes just a fertilizer application will eradicate ground ivy. As a last resort, if the weed problem is just too much, use a non-selective herbicide like glyphosate, which will kill everything. Then you can start over and create a brand-new lawn or garden bed.
