Purple Deadnettle Identification Guide
How to identify purple deadnettle (Lamium purpureum), a cool-season mint weed with reddish-purple stalked upper leaves and pink-purple flowers.
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Key Identifying Features
Purple deadnettle (Lamium purpureum) is a low winter annual in the mint family that blankets gardens and fields with reddish-purple tops in early spring. Identify it by square stems, triangular stalked upper leaves tinged purple-red crowded into a pyramid, and small pink-purple tubular flowers. It is a "deadnettle" because it resembles a nettle but does not sting.
- Low annual, usually 4-12 inches tall
- Square stems typical of mints
- Upper leaves flushed purple/red, giving the plant a purple-topped look
Leaves & Stems
Leaves are opposite, triangular to heart-shaped (spade-shaped), with scalloped to toothed margins and a softly hairy, slightly wrinkled surface. Critically, all leaves are stalked (petioled), and the upper leaves are crowded, downturned, and washed with reddish-purple, forming a layered pyramid at the stem top. Stems are square and may be purple-tinged. There is little or no minty odor.
Flowers & Fruit
From late winter into spring, purple deadnettle produces small, tubular, two-lipped pink to purple flowers about 1/2 inch long, tucked among the purplish upper leaves. Each has a hooded upper lip and a spotted lower lip, typical of mints. Fruit is a tiny four-part nutlet. The combination of purple-tinted leafy tops and small pink-purple flowers makes large patches easy to spot from a distance.
How to Tell It Apart from Look-Alikes
- Henbit (Lamium amplexicaule): closest look-alike, but its upper leaves are rounded and clasp the stem directly (stalkless), and they are green rather than strongly purple-tinged; purple deadnettle's upper leaves are triangular, stalked, and reddish-purple.
- Ground ivy/creeping Charlie: creeps flat and roots at nodes with a strong mint smell; deadnettle stands more upright with little odor.
- Wild violet: heart-shaped leaves but rounded stems and no square stem.
Where You'll Find It
Purple deadnettle favors moist, fertile, disturbed ground: gardens, crop fields, fallow land, roadsides, and lawns, in sun to part shade. It germinates in fall, overwinters, and blooms early, often turning whole fields purple in spring before dying back in summer. It is widespread across temperate North America and Eurasia and is an important early nectar source for bees.
Quick ID Checklist
- Square stems, often purple-tinged
- Opposite, triangular, stalked leaves
- Reddish-purple upper leaves crowded into a pyramid
- Small pink-purple tubular flowers in spring
- Low cool-season annual in disturbed soil
Frequently asked questions
How do I tell purple deadnettle from henbit?
Purple deadnettle has triangular, stalked upper leaves that are flushed reddish-purple, while henbit has rounded upper leaves that clasp the stem directly with no stalk and stay green. Both are square-stemmed spring mints.
Why are the top leaves purple?
The crowded upper leaves develop a reddish-purple pigment, especially in cool weather and bright light, which gives the plant its name and makes large patches look purple from a distance.
Does purple deadnettle sting like a nettle?
No. It is called a 'deadnettle' precisely because it resembles a nettle but has no stinging hairs and is completely harmless to touch.
When is purple deadnettle visible?
It is a winter annual that sprouts in fall, overwinters, and flowers in late winter through spring, often coloring fields purple before it dies back in the heat of summer.