How to get rid of creeping charley
Thank you for contacting Toronto Master Gardeners.
Creeping Charlie (its botanical name is Glechoma hederacea; another name for it is Ground Ivy) is common perennial weed plant found throughout Ontario, especially in the southern parts of the province. It grows in gardens, roadsides, waste areas, pastures, open woods and occasionally edges of cultivated fields. Spreading into gardens, lawns and shady areas, it forms large patches. Its creeping stems grow up to 30 inches long and sprawl over the soil surface becoming a tangled mat crowding out other plants. The plant is identifiable from its square stems and two kidney-shaped leaves with scalloped edges attached to stems by long leaf stalks of about 8 inches long. It has purplish-blue flowers in whorls of 2 to 6. Creeping Charlie has a minty odour when it is crushed.
The key to controlling any weed is knowing how it reproduces. You have to aim at interrupting the way the plant propagates itself. Ontario law prohibits the use of chemicals in gardens, so Toronto Master Gardeners (like other gardeners) recommend only physical and cultural forms of weed control.
Creeping Charlie reproduces by creeping stems and secondarily by seeds. Its roots are shallow, fibrous, and form at the base of nearly every leaf node on the stem. Creeping Charlie produces pods with 4 nutlets that are dark brown and have a white spot at their base.
The way to interrupt its reproduction cycle is by early mowing and hand-weeding or covering the weed with a thick layer of mulch. The surest method of controlling it is to remove the top-layer of soil containing its roots and seeds. Interestingly, in England, Creeping Charlie is considered desirable and allowed to grow as a flowering ground cover!
To learn more about Creeping Charlie, here are some links:
http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/ground_ivy.htm
https://www.oardc.ohio-state.edu/weedguide/single_weed.php?id=58