Weeds Identification Gallery

Scarlet pimpernel

  • Anagallis arvensis
  • Primrose Family: Primulaceae
Updated: 01/2026

Scarlet pimpernel is a low-growing, branching, winter or summer annual, and occasionally, biennial broadleaf plant. It is found throughout California, up to 3300 feet (1000 m), except in the deserts and possibly the Great Basin. Scarlet pimpernel inhabits agricultural land, ornamental landscape beds, turf, water body margins, and other disturbed, open areas. If consumed, it can be toxic to livestock and humans. Toxicity level ranges from virtually nontoxic to fatally toxic and appears to correlate with summer rainfall levels. Although leaves contain saponins and other potentially toxic compounds, it is uncertain as to what substance is responsible for livestock poisonings. If more palatable forage is available, livestock will avoid eating this bitter-leaved plant.

Habitat

Crop fields, vineyards, orchards, pastures, grassland, turf, gardens, landscaped areas, urban sites, roadsides, margins of vernal pools, streams, marshes, coastal terraces, ocean beaches, and other disturbed sites.

Seedling

Cotyledons (seed leaves) are narrowly lance, football or egg shaped, hairless, and 1/25 to 1/4 of an inch (1–6 mm) long. True leaves are oval to football shaped with triangular tips, are opposite to one another along the stem, and sometimes have dark glands dotting the lower surface.

Green seedling with four oval leaves with triangular tips. 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
Seedling. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Mature Plant

The mature plant grows up to 1-1/3 feet (0.4 m) tall. Stems are square in cross-section, and grow upright or prostrate. Leaves are stalkless, oval to football shaped with triangular tips, and sometimes dotted with dark or purplish glands on the lower surface. Leaves are opposite to one another along the stem, or sometimes around the stem in a whorl. Common chickweed, Stellaria media, has similar leaves but rather than the square stems and glandular hairs of scarlet pimpernel, it has round stems and nonglandular hairs.

Green leaved plant with peach-colored flowers grows from a crevice of a metal pole where it touches the ground. 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
Mature plant. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Flowers

Flowering takes place from March through July. Flowers have five salmon-orange colored petals, slender stalks, and grow singly between the stem and leaf stalks. On rare occasion flowers can be brick red, bright blue or white. They remain closed during cool or cloudy weather.

Salmon-orange colored flower with a pink center growing from a 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
Flower. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources
Salmon-orange colored flowers on their own slender stalks branch from the man stem where the leaves grow. 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
Flowering stem. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Fruits

Fruits are tiny, round capsules about 1/10 to 1/6 of an inch (3–4 mm) in diameter.  They are suspended from downward curved stalks. A lid at the top of each capsule opens and releases several seeds.

Seeds

Seeds are egg to football shaped, threesided, black or brown, 1/25 to 1/16 of an inch (1–1.5 mm) long, and covered with small wartlike projections.

Fifteen football-shaped and threesided seeds are dark  brown. The surface looks slightly spiky. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: Jack Kelly Clark, UC IPM
Seeds. Credit: Jack Kelly Clark, UC IPM

Reproduction

Reproduces by seed.

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