Bill Johnson

Ground Ivy

Glechoma hederacea L.
Mint family (Lamiaceae)

Origin: Eurasia

Background
Also known as gill-over-the-ground and creeping Charlie, it was introduced into North America as an ornamental or medicinal plant, as early as the 1800s.

Distribution and Habitat
Ground ivy occurs throughout the U.S. in all of the Lower 48 except for Nevada, Arizona and New Mexico and has been reported to be invasive in natural areas from Wisconsin to Connecticut, south to Tennessee and North Carolina. It is common in moist areas such as floodplains, low woods and disturbed sites and is a significant weed in lawns. It grows on damp, heavy, fertile and calcareous soils and does not tolerate highly acidic or saline soils.

Ecological Threat
Ground ivy is a vigorous grower that spreads across the ground forming dense patches that push out native plants. It is toxic to many vertebrates, including horses, if eaten in large quantities either fresh or in hay.

Description and Biology

• Plant: perennial scrambling herbaceous plant; stems square (4-sided) and fragile; flowering stems can reach a height of 1 ft.
• Leaves: opposite, heart-shaped with scalloped margins, about an inch across and have a musky mint odor when crushed.
• Flowers, fruits and seeds: flowers are about ½-¾ in. long, tubular, lavender, paired and emerge from leaf axils; flowering occurs March to July; each flower produces a pod containing four smooth tan seeds.
• Spreads: by vegetatively by creeping stems and to a lesser degree by seed; shallow fibrous roots form at the base of the plant and at leaf nodes on the stem.
• Look-alikes: henbit (Lamium amplexicaule), purple deadnettle (Lamium purpureum), first-year garlic mustard (Alliaria petiolata), and possibly other small herbaceous plants with opposite leaves and blue flowers.

Prevention and Control
Once established, this plant is difficult to control because it is hard to remove all root and stolon fragments. Seed banks may also remain viable after control methods are used. Small patches can be pulled by hand or using a rake when the soil is damp. All roots must be removed. Large infestations can be effectively controlled using systemic herbicides like glyphosate (see Control Options). A rust fungus Puccinia glechomatis attacks ground ivy causing severe damage or death and may hold some potential for biological control.