Giant Deadnettle, Lamium orvala

Overview

The Lamium most gardeners are familiar with is the trailing groundcover spotted deadnettle (L. maculatum). The species L. orvala, a hardy perennial native to woodlands of Central and Southern Europe, is different. This upright plant in the mint family grows in neat clumps 18 to 30 inches tall with coarsely textured, medium green foliage. The common name giant deadnettle refers to its tall, upright habit. This species is also called balm-leaved red deadnettle and clumping archangel.

Unlike its low-growing relatives, giant dead nettle has a clump-forming growth habit and does not spread. The plant produces numerous strong, generally unbranched stems each year from the deep-rooted crowns. and has a dense, nearly spherical habit that gives it the appearance of a small shrub. It is hardy in zones 4a to 8b.

The large (up to 6 inches long), alternate, ovate (pointed heart-shape) leaves are finely serrated or toothed along the margins, and covered with tiny white hairs. Prominent veins give the leaves an almost quilted appearance. The leaves are typically a solid green color, although some forms have leaves with a silver stripe down the midrib. The leaves retain a clean appearance through the growing season as long as there is sufficient soil moisture. It is considered drought tolerant but will turn yellow and spotted late in the summer if too dry.

In spring and early summer, whorls of hooded, almost orchid-like flowers are produced in whorls around the upper leaf axils, bursting from purple-pink buds surrounded by green pointed bracts (the calyx). Each velvety pink to purple flower has the two lips typical of the mint family (bilabiate). The hood-like upper lip is fringed with white hairs, while the flared, frilled lower lip sports an interesting spotted pattern. There may be sporadic flowers here and there into the fall but most of the bloom occurs early in the year. The flowers are attractive to bees.

The spiky green bracts remain after the petals fall, containing the small seeds that readily fall out as they ripen and change from green to dull brown. Some plants tend to become leggy after flowering and may flop open later in the summer.

How to use Giant Deadnettle in the Landscape

Although the flowers are very attractive, they are so ephemeral and the plant itself is bold enough that it can be utilized as a foliage plant.

Use L. orvala in shady beds and borders to provide contrast to plants with fine textured foliage or grassy leaves. Combine it with spring bulbs, ferns, and shade-loving perennials like blue or variegated hosta, astilbe, globeflower (Trollius europaeus) and Japanese forest grass (Hakonechloa macra) in the woodland garden. Pink-flowered plants that bloom at the same time, such as selected cultivars of lungwort (Pulmonaria) or several species of Geranium, will create a nice color echo to highlight the flowers.

For best growth, plant L. orvala in partial to nearly full shade in a moist but well-drained soil. It is a bit slow growing, so may take a few seasons to establish and form a large clump. Plants can be cut back after flowering, if desired, to encourage fresh, more compact foliar growth.

This plant has few insect or disease problems and is not favored by deer, but may be eaten by rabbits.

How to Propagate Giant Deadnettle

L. orvala is most often propagated by division of the clumps in early spring or fall but can be grown from seed or cuttings. It may self-seed under ideal conditions. Sow seeds outdoors in the fall or use cold, moist stratification for 4 to 6 weeks after 2 to 4 weeks of moist, warm temperature if grown indoors.

Take basal cuttings early, before the stems become hollow or take stem-tip cuttings of non-flowering stems in early summer.

Recommended Cultivars of Giant Deadnettle

A few cultivars are available, including:

• ‘Alba’ (sometimes listed as ‘Album’) has creamy white flowers and pale green leaves. It grows about 26 inches tall and 32 inches wide.
• ‘Silva’ has dusty pink flowers and an erect habit, growing 3 feet tall and about 4 feet wide. Young leaves have a subtle, short-lived silver stripe down their midribs.