Lamium (dead-nettles) is a genus of about 30 species of flowering plants in the family Lamiaceae, of which it is the type genus. They are all herbaceous plants native to Eurasia and northern Africa, with several widely naturalised across much of the temperate world.

Description

The genus includes both annual and perennial species; they spread by both seeds and stems rooting as they grow along the ground. They have square stems and coarsely textured pairs of leaves, often with striking patterns or variegation. They produce double-lipped flowers in a wide range of colours.

Taxonomy

In volume 2 of Species Plantarum published in 1753, the Swedish botanist Carl Linnaeus established genus Lamium by recognizing four species: Lamium album, Lamium purpureum, Lamium amplexicaule, and Lamium multifidum. The name Lamium L. is the primary generic name in use today. , Plants of the World Online accepts the following species: Several closely related genera were formerly included in Lamium by some botanists, including Galeopsis (hemp-nettles) and Leonurus (motherworts).

Etymology

The generic name Lamium was used by Pliny the Elder in the first century AD. The name comes from the Greek laimos, which means "gullet", a reference to the gaping throat-like appearance of the corolla. The common name "dead-nettle" has been derived from the German Taubnessel ("deaf nettle", or "nettle without a kernel"), and refers to the resemblance of Lamium album to the very distantly related stinging nettles, but unlike those, they do not have stinging hairs and so are harmless or apparently "dead".

Distribution and habitat

The species are native to Europe, Asia. and northern Africa, but several have become very successful weeds of crop fields and are now widely naturalised across much of the temperate world.

Ecology

Lamium species are used as food plants by the larvae of some Lepidoptera species including angle shades, setaceous Hebrew character and the Coleophora case-bearers C. ballotella, C. lineolea and C. ochripennella.

Cultivation

Lamium species are widely cultivated as groundcover, and numerous cultivars have been selected for garden use. They are frost hardy and grow well in most soils. Flower colour determines planting season and light requirement: white- and purple-coloured flowered species are planted in spring and prefer full sun. The yellow-flowered ones are planted in fall (autumn) and prefer shade. They often have invasive habits and need plenty of room.