Ground Ivy
Glechoma hederacea
Gill-over-the-ground. It arrived before the garden did and will remain after.
Overview
Ground ivy is a creeping mint of shaded and damp places that smells, when crushed, of something between mint and resin and the wet underside of a stone, a smell that is more particular than pleasant but thoroughly distinctive. It has nothing botanically to do with ivy — it is a mint-family herb, not a member of Araliaceae — but it spreads across shaded ground in the same carpeting manner and is equally difficult to remove once established. It was a primary ingredient in ale before hops arrived in England: gill ale, named from the Old French guiller (to ferment), was flavoured with ground ivy, which clarified, preserved, and bittered the drink. The name gill-over-the-ground preserves this history. The plant was also one of the first things recommended for a cold, for a nasal catarrh, for the cough that followed winter. It grows where it wants, and what it wants tends to be the shadowed corner where you are not looking.
Botanical Notes
A creeping, aromatic perennial with long, rooting stolons, forming dense mats in shade. Leaves are kidney-shaped, bluntly toothed, softly hairy, and pungently aromatic when crushed. Small, two-lipped, violet-blue flowers in whorls at the leaf axils from March to June. Found in shaded woodland, hedge bases, damp gardens, and waste ground throughout Europe and North America, preferring slightly moist, fertile soil. Often grows beneath elder, hawthorn, and along the bases of old walls. Contains volatile oils, bitter terpene compounds (marrubiin-related), rosmarinic acid, and flavonoids with anti-inflammatory and antioxidant activity.
Lore & History
Ground ivy appears in the earliest English herbals — the Agnus Castus and the Lacnunga both mention it for coughs and inflammation. Nicholas Culpeper assigned it to Venus, recommended it for diseases of the lungs and for hearing loss, and noted its use as a clarifying agent in ale — a use, he says, "before hops were found." This detail, in a text of 1652, places the transition from gill ale to hopped beer as recent enough to be within living memory for Culpeper's older readers. In Appalachian and American folk medicine, ground ivy tea was a standard cold and sinus remedy, carried to the New World with the settlers and adopted there as it had been adopted everywhere else the plant followed them. It is one of the more quietly continuous threads in European herbal medicine.
Warnings
Safe at normal culinary and herbal doses. The volatile oils are potentially toxic in concentrated form — the essential oil should not be used internally. Very large quantities of the fresh plant or concentrated extract have caused toxicity in livestock, particularly horses — do not overfeed as forage. At normal tea or culinary quantities, ground ivy is considered benign.