Lysimachia tenella aka Bog Pimpernel

Lysimachia tenella, listed by the RHS as Anagallis tenella, is bog pimpernel. It belongs to the primrose family, Primulaceae. The RHS also records the Welsh name gwlyddyn mair y gors. This small evergreen perennial is native to Britain and Ireland. Its low growth forms a mat rather than an upright clump. This makes it suited to ground cover in garden beds.

Plants reach about 0.33 feet (0.1 metres) in height. Their spread ranges from 0.33–1.64 feet (0.1–0.5 metres). They reach their full size within one to two years. The small, bright green leaves range from oval to rounded. The foliage stays green through winter. Deep pink flowers face upwards above the low mat. Each bloom measures about 0.03 feet (0.01 metres) across. They have a light scent and appear in late spring and early summer.

Choose a sheltered site in full sun for outdoor plants. The RHS lists south-facing and west-facing sites as suitable. Soil should hold moisture but allow excess water to drain. Moderately fertile soil suits this plant. It accepts chalk, loam, sand, and clay. It also grows across acid, neutral, and alkaline soil conditions. The RHS gives it a UK hardiness rating of H4. This covers minimum temperatures from about −10 to −5°C. Young plants should spend winter in a cool greenhouse. Plant them outdoors once the risk of frost has passed.

For growing under glass, use a gritty, peat-free, loam-based potting mix. Give greenhouse plants full light. Its low shape suits beds and borders in informal gardens. The RHS also recommends it for pots and hanging baskets. It can grow in a conservatory or greenhouse as well. These uses allow its leaves and pink flowers to form low patches. Its modest height makes it a ground-cover choice rather than a tall border plant.

Cut plants back once flowering has ended. Take softwood tip cuttings in spring or early summer. Plants may have a short life, so regular propagation helps maintain a planting. Aphids may attack the foliage, though the RHS reports few disease problems. The supplied source gives no details about fruit or seed. It also provides no evidence about edible parts or toxicity. Its garden uses should not be taken as proof of food safety.