Potentilla atrosanguinea aka Ruby Cinquefoil

Potentilla atrosanguinea belongs to the rose family. This herbaceous perennial has soft growth and lives for years. Names include Himalayan cinquefoil, ruby cinquefoil and dark crimson cinquefoil. Its native range runs from the Himalayas to Tibet. Kew places it in subalpine or subarctic climates. Missouri Botanical Garden places it on lower mountain slopes. It is not native to Britain or Ireland.

Leafy clumps spread to form low mounds. Garden plants reach about 1.5–2.5 feet [0.46–0.76 metres] tall. Missouri Botanical Garden gives a spread of 2 feet [0.61 metres]. RHS gives a larger size: 3.3 feet [1 metre] tall and wide. Long leaf stalks grow from each clump's base. Each palmate leaf has three leaflets that spread like fingers. The leaflets have toothed edges. Their tops are glossy and dark green. Pale, soft hairs coat the leaves beneath. The plant sheds its leaves for winter.

Thin, wiry stems hold loose groups of flowers above the leaves. Each flower has five petals and looks like a rose. Flowers span about three-quarters of an inch [0.019 metres]. Missouri Botanical Garden gives their colour as deep ruby red. RHS also lists orange and yellow flowers for this species. Missouri Botanical Garden gives two bloom times. Its main text says late April to June. Its summary says June to August. RHS gives the bloom time as summer. RHS warns people and pets must not eat the fruit. The fruit serves only for show.

Grow this cinquefoil in full sun for best results. It takes light shade, but not full shade. Use soil with a fair level of nutrients. It must let excess water drain away. Chalk, loam and sand can all suit it. It grows in acid, neutral and alkaline soil. Keep the soil moist. Once plants take root, they can cope with some drought. Cool northern summers suit it more than heat and humidity. Plants may struggle in hot summers south of USDA zone 7. Listed hardiness ratings are USDA zones 5–7 and RHS H7.

Its flowers suit borders, beds and rock gardens. RHS also suggests coastal gardens, banks and slopes. It lists informal wildlife gardens, too. Missouri Botanical Garden notes that the plant resists deer. It needs little care and no routine pruning. Split clumps in spring to make more plants. Plants may also seed themselves when the site suits them. Serious pests and diseases are rare, though honey fungus can occur. RHS advises gloves and other safety gear when handling the plant.