gill-over-the-ground (Glechoma hederacea)
The common name for this species, gill-over-the-ground, is more often
used in England. Most Americans call this plant simply ground ivy.
Glechoma hederacea L. var. micrantha Moric.
Glechoma hederacea L. var. parviflora (Benth.) House
Nepeta hederacea (L.) Trevis.
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name of gill-over-the-
ground is Glechoma hederacea L.
NATIVE STATUS: Introduced, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This introduced perennial plant is usually 1' or less, branching fre-
quently and forming a low-growing mat of stems and leaves across the
ground. The 4-angled stems are prostrate to slightly ascending, and often
form rootlets near the axils of the leaves when they touch the ground.
Leaves: The opposite leaves are about 1" long and across. They are green
to purplish green, orbicular, and crenate along the margins. There is a flat indentation where the long petiole joins the base of a leaf. The pubescent
upper surface has conspicuous palmate venation.
Flowers: Clusters of 1-3 tubular flowers develop from the leaf axils. These flowers are bluish violet to reddish purple and about ½" in length. The
corolla of each flower is narrow at the base, but flares outward like a trum-
pet into spreading lobes. There is a notched upper lobe, a notched lower
lobe, and 2 smaller side lobes. The lower lobe is larger than the others and functions as a landing pad for visiting insects. It has darker violet lines that function as nectar guides. Within the throat of the corolla, there are fuzzy
hairs. Each flower has a single pistil with a divided style, 2 long stamens,
and 2 short stamens. The pubescent calyx is about 1/3 the length of the
tubular corolla, with 15 veins running along its length and 5 teeth along
its outer edge.
Fruit/Seeds: Upon maturity, each flower is replaced by 4 dark brown nut-
lets. Each nutlet is ovoid, with 2 flat sides and an outer side that is rounded.
Roots: The root system is fibrous and shallow. This plant often forms
dense colonies by forming rootlets along the stems.
REGENERATION PROCESS: Gill-over-the-ground propogates itself
HABITAT TYPES: Habitats include openings of floodplain forests, semi-
shaded areas along rivers, powerline clearances in woodland areas, ceme-
teries, lawns and gardens, and miscellaneous waste areas. This plant can
withstand regular mowing, but flourishes better without it. It prefers dis-
turbed areas, but occasionally invades higher quality natural areas. Some-
times homeowners tolerate its presence in lawns because they like the
SITE CHARACTERISTICS: Gill-over-the-ground prefers partial sun,
moist conditions, and fertile loamy soil in an open situation where there is
little ground cover. This species can spread aggressively and is difficult to
destroy without resorting to herbicides. During hot summer weather, it
has a tendency to become dormant.
SEASONAL DEVELOPMENT: The blooming period usually occurs
from mid-spring to early summer for about 2 months, although some
plants may bloom later in the year if they remain in cool shade or a major
disturbance prevents earlier bloom.
GENERAL DISTRIBUTION: Except in the extreme southwestern
states (New Mexico, Arizona, and Nevada), gill-over-the-ground is found
throughout the continental United States and all the southern Canadian
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Gill-over-the-ground is an important
source of nectar during the spring for bees. Otherwise, its ecological
value is rather low. The size and color of the flowers are somewhat
variable. This species resembles another introduced member of the
Mint Family, Lamium amplexicaule (henbit), which is also an aggres-
sive spreader. However, the opposite leaves of henbit are more widely
spaced along its spreading stems and they strongly clasp the stems,
while the leaves of gill-over-the-ground have long petioles. The flow-
ers of henbit occur in whorls from the axils of the upper leaves, and
they are more erect and pink than the flowers of gill-over-the-fround.
Other members of the Mint Family usually have an erect habit, while
the stems of gill-over-the- ground often sprawl about and form loose
The nectar of the flowers attracts long-tongued bees primarily, including
honeybees, bumblebees, mason bees, cuckoo bees (Nomadine), miner
bees, and Anthophorid bees. Occasionally, the flowers attract bee flies,
skippers, sulfur butterflies, and white butterflies, especially Pieris rapae
(cabbage white). The caterpillars of the moth Xanthotype urticaria (false
crocus geometer) feed on the foliage. The foliage is reportedly poisonous
to horses if it is eaten in quantity.
Crooked Run Valley