Scarlet pimpernel / Spring / Summer / Toxic
The Scarlet Pimpernel (Anagallis arvensis) is a charming wildflower often spotted brightening up fields, gardens, and roadside verges across the UK. With its vivid orange-red flowers and creeping habit, it’s hard to miss and often mistaken for an edible herb by novice foragers.
However, despite its delicate beauty, this plant is toxic and should never be consumed. Ingesting it can lead to stomach irritation and other adverse effects.
Fascinatingly, the Scarlet Pimpernel has a long history in folklore, often referred to as the “Poor Man’s Weather Glass” because its flowers close in dull or rainy weather.
In this post, we’ll explore how to identify this striking plant, where it grows, and why it’s one to admire but not to pick for your plate.
Common Names
Scarlet pimpernel, Shepherd’s sundial, Shepherd’s weather-glass
Latin Name
Anagallis arvensis
Family
Primulaceae otherwise known as the Primrose family
Physical Characteristics of Scarlet pimpernel
Low growing delicate annual with a creeping habit, spread is about 15-30cm
Leaves
Smooth ovate leaf shape, in opposite pairs and attached directly to the stem with no leaf stem (sessile) bright green and hairless .

Stem
Spreads out and divides staying contained and low lying. Square cross section, but being so small you may need a magnifying glass to see this. Hairless.
Flowers


מרגנית השדה – עין התכלת
Horashim Forest, Israel, 2014
יער חורשים, ישראל, 2014
Most commonly orange can also be red or blue flowers with five petals. Each petal has a pinky colouring towards the centre, with 5 closely positioned stamen protruding from the centre. Flowers are small 10-15 mm and appears singularly from the leaf axis.
Fruit
Dry seed capsule
Habitat, Range and Distribution
It can be found in many places such as arable fields, woodland, on roadside verges and waste ground, and on coastal cliffs. It is an indicator species of light soils but will tolerate most.
Scarlet pimpernel Could Be Confused With
Chickweed -Stellaria media. When not in flower they look very similar. To tell the difference you will need to take a very close look at the stem. Chickweed has a hairy line running along the stem while Scarlet pimpernel is hairless. Once in flower the difference is very obvious as chickweed has very small white flowers. Chickweed is a lovely salad edible.

Safety Notes
Do not ingest any part, also may cause dermatitis in sensitive individuals.
Edible Uses
Whole plant is toxic, in varying amount depending on how dry or moist the plant is.
Conservation Considerations
Once considered a weed of farmers fields, the Scarlet pimpernel is now in decline due to intensive agricultural practices.
Extra Tips and Fun Facts
The names shepherd’s sundial and shepherd’s weather-glass came about because the flowers close at 3pm and if the weather is damp or humid. Also because the flowers have a protruding center of stamen these were used like a sundial to tell the time .
The name pimpernel comes from the Old French pimprenele, the misapplied name of the burnet saxifrage, Pimpinella saxifrage
Scarlet pimpernel has been used by the ancient Greeks for medicinal use, the young leave also used to be eaten after being boiled however this plant has since been proven to have many harmful side-effects.
Resources
https://www.inaturalist.org/guide_taxa/183838
https://www.wildlifetrusts.org/wildlife-explorer/wildflowers/scarlet-pimpernel