Ajuga reptans has dark green leaves with purple highlights. It is a spreading ground cover that grows in a dense mat. The leaves grow 5-8 cm (2.0-3.1 in) high but in the spring it sends up 10-15 cm (3.9-5.9 in) tall flower stalks with many purple flowers on them. The flowers are frequently visited by flies, such as Rhingia campestris.Ajuga reptans, commonly known as bugle, blue bugle, bugleherb, bugleweed, carpetweed, carpet bugleweed, common bugle, is an herbaceous flowering plant native to Europe. It is invasive in parts of North America. Grown as a garden plant it provides useful groundcover. Numerous cultivars have been selected, of which "Caitlin's Giant" has gained the Royal Horticultural Society's Award of Garden Merit.Ajuga reptans is also a component of purple moor grass and rush pastures, a Biodiversity Action Plan habitat in the United Kingdom.
Ajuga reptans is a sprawling perennial plant with erect flowering stems and grows to a height of about 10 to 35 cm (4 to 14 in). The stems are squarish with hairs on two sides and the plant has runners that spread across the surface of the ground. The purplish-green, stalked leaves are in opposite pairs. The leaf blades are hairless and are elliptical or ovate with a rounded tip and shallowly rounded teeth on the margin. The inflorescence forms a dense raceme and is composed of whorls of blue flowers, each with dark veins on the lower lip. The calyx has five toothed lobes and the corolla forms a two-lipped flower about 14 to 17 mm (0.6 to 0.7 in) long with a short tube. The upper lip of each flower is short and flat with a smooth edge and the lower lip is three-lobed, the central lobe being the largest, flat with a notched tip. There are four stamens, two long and two short, which are longer than the corolla and are attached to the tube. The ovary is superior and the fruit is a schizocarp with four chambers.
Bugle is also known as "carpenter's herb" due to its supposed ability to stem bleeding.
Bugle is a primary nectar source of the pearl-bordered fritillary and the small pearl-bordered fritillary. It is a secondary nectar source of the brimstone, chequered skipper, common blue, cryptic wood white, dingy skipper, Duke of Burgundy, green-veined white, grizzled skipper, heath fritillary, holly blue, large blue, large skipper, large white, marsh fritillary, orange-tip, painted lady, small white, and wood white butterflies.
Ajuga reptans herb has been used in traditional Austrian medicine internally as a tea for the treatment of disorders related to the respiratory tract.