- Name also: Moneywort, Herb Twopence, Twopenny Grass
- Family: Primrose Family – Primulaceae
- Growing form: Perennial herb. Rootstock long. Long runners.
- Height: 50–160 cm (20–65 in.) long. Stem limp, creeping, sometimes rooting, almost glabrous.
- Flower: Corolla wheel-shaped, yellow and dark-spotted, 20–30 mm (0.8–1.2 in.) wide, fused, short-tubed, 5-lobed, lobes with roundish tips, short-haired. Calyx lobes cordate. Stamens 5. Pistil a fused carpel. Flowers solitary or in pairs in axils.
- Leaves: Opposite, short-stalked. Leaf blade ovate–virtually round, with round or cordate base, dark-spotted, with entire margins.
- Fruit: Spherical, 5-valved, capsule shorter than calyx. Rarely develops.
- Habitat: Lawns, ditch banks, meadows, shores, broad-leaved forests, rocky ridges. Ornamental and an escape from cultivation.
- Flowering time: July–September.
Finland’s native genus Lysimachia plants are erect-stemmed wetland plants. Creeping Jenny was brought to Finland as an ornamental, and its limp stem creeps along the ground. Another obvious difference is the shape of the leaves: other Finnish species in the genus are ovate or lanceolate, but creeping Jenny’s blades are often small and roundish like a coin – which is also where its scientific name comes from. Examining the flowers however shows how it is related to other genus Lysimachia plants.
Creeping Jenny grows as a native in rich broad-leaved forests of Denmark and southern Sweden. It has been observed to be an undemanding garden plant which does best on sufficiently damp, semi-shaded or even shaded places. The species thrives so well in Finland that it has escaped in many places in southern and central Finland to lawns, parks, yards and waste ground.
There is a botanical book from the Middle Ages that calls creeping Jenny Centrum Morbidium, which freely translates as ‘healer of a hundred maladies’. It was used to treat e.g. gout and bleeding. Many other plants in the same genus also have medicinal properties.