This aggressive, smelly weed is a perennial problem CREEPING CHARLIE

By Marilyn McKinley

OSU master gardener volunteer

Is there a garden in the Midwest that has not been invaded by Creeping Charllie – the aggressive, smelly weed?

Now that dandelions have calmed, we are left with just a few bad weeds. To me, this one is the worst!

A member of the mint family (look for the square stems), Creeping Charlie seems to grow everywhere.

It does best in moist, shaded areas, but sun is no problem, nor is a lawn, or cracks in the sidewalk at my house.

This perennial weed is a European native brought to America by early settlers who thought it to be a good ground cover.

The plant was thought to have some medicinal qualities in ancient Greece and Rome. It was recommended for ringing in the ears, inflamed eyes and as a diuretic and astringent. It also was used, as hops are used today, to clarify beers back in the day.

Also known as ground ivy and garden ivy, this is a difficult weed to control.

Don’t let the dainty little purple flower fool you! It persistently propagates itself by seeding and rooting at the nodes that stud its long vines.

It will regrow from small pieces of vegetation left behind after removal.

Mowing seems to encourage more growth of the vines.

It can be found in lawns where grass is thin and not very robust.

Another name for this plant is catsfoot – the leaf resembles a kitten’s paw, but if you pull it out by hand or mow over it, the distant aroma of what reminds one of cat’s urine wafts through the air. Not my favorite smell in the garden.

Though pulling can work as a cultural control, it takes a long, long time.

Additionally, plants must be disposed of, as they can re-root if left in certain places.

If a problem in lawns, you need to raise the mower to 3 inches.

Maintaining a healthy lawn and using shade tolerate grasses will help as well.

Learn to manage your lawn, and you’ll crowd out Creeping Charlie.

If cultural controls do not work, consider a systemic, selective broadleaf herbicide. These herbicides are taken up by the plant and will kill the entire plant, roots to flowers.

Autumn is the best time for treatment as this is when the plant is actively taking in nutrients from the soil in preparation to sustain it over the winter.

Spring is the second choice for treatment.

For treatment of small areas growing in the lawn, you can use a selective herbicide, but you may need two or three treatments.

Chelated iron is the active ingredient in some natural, broadleaf herbicides. Since there is no residual activity of these products, you will need to apply each time you see new weeds.

The lawn may show some burning, but will recover.

The entire lawn should be sprayed, or you’ll end up with dark spots in the lawn.

Some grasses are not tolerant of this type of herbicide.

Borax (boron) is a product that used to be recommended to kill Creeping Charlie. However, research has shown that addition of boron to the soil can create unfavorable growing environments and make it difficult to re-establish lawns. Thus, this is no longer recommended.

Be sure to read and follow all label information when using any herbicide – organic or conventional.

For more on creeping Charlie, go to http://go.osu.edu/creepingcharlie.

For more on natural, iron based herbicides, go to http://go.osu.edu/ironbased.