Scarlet Pimpernel (Poor Man’s Weatherglass)

Scarlet pimpernel flower and foliage
Scientific Name
Anagallis arvensis (Lysamachia arvensis)
Primulaceae (Primroses)

Scarlet pimpernel is a tender annual, branched from the base, with square stems. The flowers arise singly at the tips of long stems that arise from leaf axils; the petals are united at their base to form a very short tube, thus the corolla is technically deeply 5-lobed; flowers are less than ½ inch wide; scarlet or brick red, rarely white or bluish. Blooms May–September. Leaves are opposite, stalkless, ovate, with dots underneath, with or without hairs, to ¾ inch long. The fruit is a tiny, round capsule that opens its “lid” to disperse seeds.


Height: to about 6 inches.

Where To Find
image of Scarlet Pimpernel Poor Man’s Weatherglass distribution map

Occurs in central, east-central, and southern Missouri.

Found in fields, pastures, waste places, rights-of-way, and other disturbed sites, usually in moist soils. This plant can develop roots at the stem nodes and spread to form a mat. A native of Eurasia, this plant has been spread all over the world where the climate is suitable.

This plant has a long history as a medicinal herb that goes back to the Greek scholars Pliny and Dioscorides. Over the centuries and in various countries, it has been used as a remedy for poor complexion, depression, rabies, weak vision, hard-to-remove splinters — and even witchcraft.

The name "pimpernel" is a form of the original Latin name for this plant. In the early 1900s, a novel, stage play, and, later, musicals, movies, and TV shows, set in France during the Reign of Terror, depicted a fictional masked hero called "The Scarlet Pimpernel." This was an early version of what has become the well-known trope of "hero with a secret identity." In The Scarlet Pimpernel, the mysterious, dashing hero is a mild-mannered Englishman who, as the masked hero, rescues French aristocrats from the guillotine. He signs his letters only with a drawing of this little red flower, so common in Europe.

The flowers close around 4 p.m., or whenever clouds shade the sun. When the sun comes out again, they reopen — hence the common name "weatherglass." This adaption probably helps the plant maximize the amount of pollination that can occur while lengthening the life of each flower.

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About Wildflowers, Grasses and Other Nonwoody Plants in Missouri
A very simple way of thinking about the green world is to divide the vascular plants into two groups: woody and nonwoody (or herbaceous). But this is an artificial division; many plant families include some species that are woody and some that are not. The diversity of nonwoody vascular plants is staggering! Think of all the ferns, grasses, sedges, lilies, peas, sunflowers, nightshades, milkweeds, mustards, mints, and mallows — weeds and wildflowers — and many more!