Scientific Family
Urticaceae
Synonyms
Urtica californica, U. gracilis, U. lyallii, U.major, U.procera, U. viridis
Other common names
tall white nettle
American stinging nettle
coast nettle
Lyall nettle
Plant type
Forbs and Subshrubs
Origin
Introduced
Lifecycle
Perennial
Similar species
Urtica serra
Height
1-1/2 to 6 feet
Riparian
Yes
Grows in colonies through horizontal underground stems (rhizomes); has an upright to sprawling growth pattern and may be branched or unbranched; leaves and stems are covered with sharp, stinging hairs which can cause a painful rash if touched.
Perennial, rhizomatous, flower stems unisexual, male and female on same or different plants, male ascending, female lax or recurved. Leaves opposite, pointed, with toothed margins; covered in visible stinging and non-stinging hairs.
Habitat
Moist uncultivated areas including waste and sewage sites, dumps, fence rows, roadsides, riverbanks, along streams and bogs as well as the margins of deciduous woodlands and mountain slopes.
Plant Community
Riparian
Pinyon Juniper Woodlands
Montane Conifer Forest
Disturbed Areas
Low elevation
0
High elevation
9000
Flower Characteristics
Tiny flowers to 1/8 inch wide have no petals, grow in drooping clusters at the bases of the leafstalks; male and female flowers grow on separate branches of the same plant or on different plants; male flowers grow upward, female flowers curve backwards.
Flower color
Reddish-brown to greenish-white
Flower shape
Inconspicuous
Tubular
No
First bloom month
May
Last bloom month
August
Flower clusters
Elongated
Leaf and Stem Characteristics
Leaves 2-1/2 to 5 inches long, tips pointed, 3 to 5 prominent veins radiate from a rounded and slightly heart-shaped base, hairless above with stinging and non-stinging hairs below. Stems smooth or have sharp, stiff, flat stinging hairs.
Leaf type
Simple
Leaf color
Dark green
Leaf shape
Round or oval
Leaf margin
Toothed
Leaves clasp
No
Leaf hairs
Leaves & stems
Spines
No
Fruit and Seed Characteristics
Egg-shaped fruit less than 1/16 inch long with 1 hard seed, short stalked. Seeds easily detach from the thin, dry husk.
Fruit type
Achene
Fruit color
Greenish-brown
Nettle produces abundant seed; in full sunlight can produce 10,000 to 20,000 seeds per stem and 500 to 5,000 seeds when growing in shade. Seeds remain on the plant until frost when they fall to the ground; seeds can germinate 5 to 10 days after maturity.