Managing Difficult Summer Lawn Weeds

Urbana-Champaign, Illinois (July 18, 2011)--Some weeds in the lawn seem almost impossible to control. Rhonda Ferree, extension educator in horticulture, says that she is often asked how to control Creeping Charlie and white clover growing in the lawn. Here are some tips that might help in your fight with these weeds.

Creeping Charlie, also called ground ivy, is a mint that forms large mats and is incredibly invasive. It creeps on stems that can grow up to 2 and one-half feet long. The leaves are round to somewhat kidney-shaped with round, toothed margins. It has small funnel-shaped purplish-blue flowers from April to June. Ground ivy is typically more of a problem in shaded sites with poorly drained, fertile soils, although it can spread to sunny locations.

White clover, like ground ivy, grows from seed and creeping stems. White clover was formerly a common component of turf mixes, due to its ability to fix nitrogen. It is most commonly found in moist, low-fertility soils. The leaves are a typical three-part clover and it has white ball-shaped flowers from May to September.

To manage these weeds (and other broadleaves in the lawn), try a combination of chemical and non-chemical management options. First, find out why the weeds are there. Some weeds are indicators of soil problems. For example, plantains grow in low-fertility soils and proper fertilization is the first step to control it. Ground ivy prefers shady, wet areas so one management option is to alter the problem area by reducing shade and soil moisture.

Step two is to make sure your lawn is healthy and competitive. Healthy, full grass will out compete most types of weeds. In turf areas, maintain turf density and health through proper lawn care practices such as proper selection and establishment, watering, mowing, fertilization, and related practices.

The third step is actually removing the weeds. Pulling by hand is one option, but be sure to get as much of the plant and root system as possible. Pull up every stem you see and destroy them (do not put them into the compost!). Continue routing out the difficult weeds once a month all summer and again the following year.

Finally, chemical control may be necessary. However, since the weeds must be actively growing in order for the herbicide to work, herbicides should be applied in midspring to early summer and/or mid-to-late autumn. A treatment in mid-summer will not work. For the lawn, use a product containing a combination of two or more products: 2,4-D, mecoprop or MCPP, or dicamba. Difficult weeds such as ground ivy and white clover often need more than just 2,4-D in the tank mix.

Finally, remember that the above mentioned products should only be used in turf areas. Not only could they damage or kill many desirable ornamentals or edible plants in the landscape, but also those applications are illegal. For more information about controlling weeds in the lawn or other garden areas, contact your local Extension office by visiting www.extension.illinois.edu. You can also post questions on Rhonda's facebook page at www.facebook.com/ferree.horticulture.

Contact:

Rhonda J. Ferree
ferreer@illinois.edu