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Glechoma hederacea is an aromatic, perennial, evergreen creeper of the mint family Lamiaceae. It is commonly known as ground-ivy, gill-over-the-ground, creeping charlie, alehoof, tunhoof, catsfoot, field balm, and run-away-robin. herbicides are relied upon (despite their drawbacks) particularly for woodland ecosystems. The plant's extensive root system makes it difficult to eradicate by hand-pulling.

Description

Glechoma hederacea can be identified by its round to reniform (kidney- or fan-shaped), crenate (with round-toothed edges) opposed leaves diameter, on long petioles attached to square stems that root at the nodes. The plant spreads either by stolon or seed, making it exceptionally difficult to eradicate. It is a variable species, its size being influenced by environmental conditions, from tall.

The flowers of G. hederacea are bilaterally symmetrical, funnel shaped, blue or bluish-violet to lavender, and grow in opposed clusters of two or three flowers in the leaf axils on the upper part of the stem or near the tip. It usually flowers in the spring.

Reproduction

Glechoma hederecea is gynodioecious, with genets being either female or hermaphrodite. The females depend upon pollen from hermaphrodites for pollination. Each pollinated flower can produce up to four seeds, which are dispersed by the stem bending over and depositing the ripe seeds in the ground adjacent to the parent plant, although ants may carry the seeds further. The seeds germinate a few days after contact with moisture, although they can be stored dry. It has invaded wild areas, sometimes choking out native wildflowers.

G. hederacea thrives in moist shaded areas, but also tolerates sun very well. It is a common plant in grasslands and wooded areas or wasteland. It also thrives in lawns and around buildings, since it survives mowing. Part of the reason for its wide distribution is its rhizomatous method of reproduction.

Ecology

A number of wild bees collect pollen from this plant, including Anthophora furcata, Anthidum manicatum, Anthophora plumipes, Anthophora quadrimaculata, Osmia aurulenta, Osmia caerulentes, and Osmia uncinata. The plant is also galled by several insects, including Rondaniola bursaria (lighthouse gall), Liposthenes glechomae or Liposthenes latreillei (Kieffer, 1898) (a gall wasp).

It forms dense mats that can take over areas of lawn and woodlands, thus is considered an invasive or aggressive weed in suitable climates where it is not native. recent research discounts the very efficacy of borax treatment, primarily because finding the correct concentration for a given area is difficult and the potential for damaging desired plants is high.

Safety

Although it has been used by humans as a salad green and in herbal medicines for thousands of years, the species is also believed to be toxic to livestock, particularly horses. Wild pigs, however, are reported to feed on it. Some accounts report it is toxic to rodents, while bank voles in Great Britain have been observed to use it as a food source. Other members of the Lamiacaeae, such as Mentha spicata, spearmint, are widely and safely used in teas and flavorings for their volatile oils. The concentration of volatile oil in G. hederacea is less than 1/30th that in European pennyroyal. The effects of Glechoma on humans have been little studied.

Uses

right|thumb|Botanical illustration

It is grown as a garden plant in pots and occasionally as a groundcover. Easily cultivated, it grows well in shaded places. A variegated variety is commercially available; in many areas, this is the dominant form, which has escaped cultivation and become established as an aggressive, adventitious groundcover.

The pre-bloom leaves can be cooked as a vegetable or made into tea.

G. hederacea was also widely used by the Saxons in brewing ale as flavoring, clarification, and preservative, and later by the English, before the introduction of hops into brewing in the late 15th century. From this, the brewing-related names arose for the herb, e.g. alehoof, tunhoof, and gill-over-the-ground. In the 18th century, beer brewed with ground ivy was known as gill ale and was said to have medicinal properties. It was made by infusing the herb in strong ale and was sold at coffee and victualling houses.

Enzymes similar to chymosin in G. hederacea have been used in the cheese-making process as a substitute for animal rennet.

thumb|right|G. hederacea [[seedling - cot = cotyledons; ga = axillary bud, from (Warming 1884)]]

Traditional medicine

G. hederacea has been used in the traditional medicine of Europe going back thousands of years; Galen recommends the plant to treat inflammation of the eyes. John Gerard, an English herbalist, recommended it to treat tinnitus, and as a "diuretic, astringent, tonic, and gentle stimulant. Useful in kidney diseases and for indigestion." It has also been used as a "lung herb". Its presence as an invasive weed in North America is the result of the value placed on it by European settlers as a medicinal herb and ale preservative; the species was imported and widely cultivated in herb and kitchen gardens. Its other traditional uses include as an expectorant or astringent, and to treat bronchitis. In traditional Chinese medicine, it is known as Jiangsu Jinqiancao.

References

Further reading

  • Ground Ivy: Glechoma hederacea
  • Questions on: Ground Ivy
  • Attempting Ground Ivy Control
  • Glechoma hederacea
  • Using Borax to Control Creeping Charlie