You may be surprised to learn that early colonists brought ground
ivy with them for culinary and medicinal purposes.
It was used to flavor beer for many
years, until it was replaced by hops. Although it is not native to
North America, ground ivy has naturalized and is found throughout
Pennsylvania, the northeastern United States, and southern Canada.
While ground ivy prefers damp, rich soils, and thrives in the
shade, it will grow in full sun and less than ideal soil just as
Ground Ivy taking over a lawn
Left to its own
devices, ground ivy forms a dense mat that quickly crowds out other
plants. Getting it under control in a lawn situation is not simply a
matter of getting rid of the ground ivy. It is equally important to
follow best practices for maintaining a healthy lawn, or else
the ground ivy will grow back from seed and you will be back to
Cultural practices that help your lawn
• Raising your
mower's cutting height to 2.5 to 3 inches. The taller height of cut
allows the grass to shade out germinating weed seeds and helps it
maintain a more extensive root system. A more extensive root system
helps your lawn survive summer heat and drought.
• Try not to
remove more than one-third of the grass blade at one time - this may
mean that you have to mow more frequently when the grass is growing
vigorously in spring. Staying within the "one-third rule" allows the
grass to maintain a healthy reserve of carbohydrates.
• Have your
soil tested and follow the recommendations for limestone to raise
soil pH (or sulfur to lower soil pH) and fertilizer applications.
Maintaining proper soil pH and fertility levels is important for
optimum performance of your lawn.
• If the area
stays moist, take steps to improve drainage in the area. Soil that
stays constantly moist favors the growth of ground ivy and can cause
grass roots to rot.
• If the area
is heavily shaded, consult with a certified arborist to thin and
raise the crown of large trees. If that is not an option, consider
replacing the grass with shade-tolerant ground covers such as wild
ginger (Asarum canadense), European ginger (Asarum europaeum), sweet
woodruff (Galium odoratum), hostas (Hosta spp.), creeping lily-turf
(Liriope spicata), Japanese pachysandra (Pachysandra terminalis),
Allegheny foamflower (Tiarella cordifolia), creeping myrtle (Vinca
minor), or Barren Strawberry (Waldsteinia fragarioides).
There are a few options for getting rid of the ground ivy, including
hand weeding. Although it is monotonous, pulling ground ivy by hand
will eventually get rid of it, but you have to stay on top of it.
Hand weeding is the best option in flower beds, vegetable
gardens, and shrub borders, because the herbicides that safely kill
ground ivy in lawns would damage desirable plants in those areas.
Repeated applications of broadleaf weed killers can be the
most effective way to get rid of ground ivy in lawns. These are
products that kill broadleaf weeds such as ground ivy, dandelions
and plantain without harming lawn grasses. While one application can
take care of many weeds, ground ivy is usually tougher to get rid
of. Two or more applications may be required to achieve a
satisfactory level of control. Make additional applications at the
shortest interval recommended on the label of the product you are
using. While many broadleaf weed control products are based on 2,4-D
herbicide, there are other products that are more effective when it
comes to controlling ground ivy. Broadleaf weed control products
that contain triclopyr, such as Ortho Weed-B-Gon Chickweed, Clover
and Oxalis Killer have proven effective. So has a relatively new
product on the homeowner market, Ortho Weed-B-Gon MAX Plus Crabgrass
Control. It contains quniclorac, along with 2,4-D, MCPP and dicamba.
Careful timing of those applications is essential for optimum
control. Late summer to early fall (mid-September to mid-October in
Pennsylvania) has long been recognized as the best time to control
tough-to-kill weeds such as ground ivy and clover. At that time of
year, plants are translocating the carbohydrates produced by
photosynthesis down to their roots for storage. Consequently, they
readily absorb herbicides and move them down to the roots, which
kills the weed, root and all. Cornell's Dr. Frank Rossi has
conducted research that shows good control of ground ivy with spring
applications made when it is in bloom. Those small, purplish-blue
flowers appear sometime in May. That makes sense, too, because the
ground ivy has used much of its stored carbohydrates to push new
growth in spring. Blooming is a further strain on those reserves. As
a result, a properly timed herbicide application can deliver a
knockout punch - even to a tough customer like ground ivy.