Purple Deadnettle

Mint (Lamiaceae family):

Lamium purpureum L.

EPPO code:

LAMPU

Other names:

Red dead-nettle, red nettle, purple archangel

Species information

Lifecycle:

Winter annual.

Propagation:

Reproduces by seed.

Emergence:

Germinates in the fall.

Habitat:

Native to Eurasia, purple deadnettle is now common in North America. It is found in fields, gardens and turf grass.

Competitiveness:

Similar to henbit, purple deadnettle is also an alternate host for soybean cyst nematode.

Identification clues

Seedling

Cotyledons:

Oval to round, with two small lobes at the base and a long stalk. Hairless.

First leaves:

The first leaves have an opposite orientation. They appear on short stalks and are triangular to heart-shaped with rounded teeth. The leaf surface is hairy.

Mature plant

Mature leaves:

They grow in an opposite orientation; the upper leaves are heart-shaped, densely covered with hairs and petiolated; as they reach the top of the stems, the leaves are smaller, more overlapped and develop a red or purple tinge. Opposite leaf orientation; leaves grow on stalks and are circular to heart-shaped.

Stem:

Branched and square in cross-section.

Flowers:

Pink to purple in colour, purple deadnettle’s flowers appear as whorls in the upper leaf axils. The plant flowers in early spring.

Roots:

Fibrous taproot

Often mistaken for

I know it's not Henbit because although henbit and deadnettle both have square stems and flower in the early spring, the upper leaves of deadnettle usually have a red to purple tinge to them, are triangular and grow on leaf stalks, whereas henbit’s leaves are green and lack stalks.