Weeds Identification Gallery

Mouseear Chickweed

  • Cerastium fontanum ssp. vulgare
  • Pink Family: Caryophyllaceae
Updated: 10/2025

Mouseear chickweed is a prostrate perennial broadleaf plant that can behave like a biennial or annual in disturbed places. In California, it is found in the northwestern region, Cascade Range, and Sierra Nevada, up to 7200 feet (about 2200 m). It probably also occurs in the southern Central Coast, South Coast Ranges, and southern South Coast. Mouseear chickweed inhabits agricultural land and other disturbed sites.

Habitat

Turf, gardens, landscaped areas, agronomic and vegetable crop fields, orchards, vineyards, grasslands, wet soil near marshes, moist woodlands, managed forests, nurseries, roadsides, and other disturbed places.

Seedling

Cotyledons (seed leaves) are rounded and either lack hairs or have very few hairs. The first and next few leaf pairs are oval to narrowly football-shaped, with abruptly pointed tips and long hairs. Leaf stalks are equal in length to the leaf blades. True leaves are opposite to one another along the stem, have rounded tips, and are stalkless.

Seedling showing round leaves with soft hairs, 1X; . Credit: Jack Kelly Clark, UC IPM
Seedling, Credit: Jack Kelly Clark, UC IPM

Mature Plant

Mouseear chickweed grows up to about 20 inches (0.5 m) long. It is a hairy plant with creeping matlike stems that root from the stem joints (nodes). Stems are mostly forked and leaves are opposite to one another along the stem. Leaves are either stalkless or have a short stalk. Although similar in form to common chickweed, Stellaria media, mouseear chickweed can be distinguished by its hairy leaves and stems (common chickweed stems have one line of hairs on either side and leaves are hairless or have hairs only on the edge of the leaf near the base).

Close up of a plant with star-shaped green leaves and small white flowers.  Copyright information is at the bottom (Copyright 2000 UC Statewide IPM Program, Regents, University of California.). Credit: Jack Kelly Clark, UC IPM
Mature plant. Credit: Jack Kelly Clark, UC IPM

Flowers

Mouseear chickweed blooms from March to August. Flowers are produced in open clusters at the end of the stem. Small, inconspicuous flowers appear to have 10 petals, but are really 5 deeply divided white petals.

Close up of a small white flower with five petals and green buds against dark green foliage. Each petal is deeply lobed appearing almost as two separate petals. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources
Flower. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Fruits

Fruits consist of cylindrical capsules, roughly 1/4 to 3/7 of an inch (6.5-11 mm) long, and contain numerous minute seeds. The open tip of the fruit is surrounded by ten teeth.

Close up of a small, fuzzy plant bud set against a dark background. The bud is partially opened, with small spikes on end furtherest away from the stem. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources
Fruit capsule. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Seeds

Seeds are tiny, about 1/25 of an inch (1 mm) long or less, triangular to egg-shaped, and reddish brown. Under magnification, minute nipplelike projections can be seen covering the surface.

Nine small, brown seeds with a wrinkled texture scattered on a gray background. A 1 millimeters scale for size reference is included and shows the seed are around 1 millimeters. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: James A. O'Brien, University of California
Seeds. Credit: James A. O'Brien, University of California

Reproduction

Mouseear chickweed reproduces by seed, but sometimes reproduces by creeping stems that root from the stem joints (nodes).

More Information