Lamium galeobdolon aka Yellow Archangel

Lamium galeobdolon, or yellow archangel, belongs to the mint family. This perennial grows across Europe, western Siberia, and Iran. It is native to Britain and Ireland. Wild plants grow in woods, hedges, and grassy banks. They often grow on heavier soils and can dominate cleared woodland. Gardeners use it as ground cover in shade. Its fast growth makes it less suited to small borders.

Plants reach about 1–2 feet [0.3–0.6 metres] tall. Published garden spreads range from 1–3.3 feet [0.3–1 metre]. Upright and creeping stems form a spreading mat. Stems root where they meet the soil. They have four sides and a coat of white hairs. Green leaves grow in pairs along the stems. Each leaf has a toothed edge and a hairy surface. Leaves measure 1–3 inches long and release scent when crushed. RHS describes the foliage as deciduous; NC State lists it as evergreen.

Yellow flowers open from late spring into early summer. One garden source lists June as the bloom month. Flowers gather in rings where leaves join the stems. Each flower has two lips and a hooded upper lip. The lower lip spreads out and has three lobes. Brown flecks mark the yellow corolla. Individual flowers measure less than an inch across. Their bright colour adds interest to shaded woodland beds.

This plant grows in partial or full shade. NC State reports that it does not tolerate full sun. It accepts clay, loam, sand, and chalk soils. Acid, neutral, and alkaline soils all suit it. Moist soil with good drainage supports growth, but plants tolerate drought. They also cope with dry shade and shallow, rocky soil. Sources rate it for USDA zones 4–9 and UK H7. Divide plants in spring to make new ones. Cut back untidy growth or trim at the season's end.

Its spreading cover suits slopes and large shaded spaces. Yet runners can crowd out smaller plants. Parts of the western United States list it as invasive. Most sources report few serious pest or disease problems. Slugs, snails, mites, and leaf blight may occur. Plants For A Future lists cooked young leaves and shoots as edible. It also lists flowers and cooked young flowering tips. That source reports no known hazards, but does not establish pet safety.