Parnassia palustris aka Grass Of Parnassus

Parnassia palustris is a small perennial called grass of Parnassus. It belongs to the Celastraceae family. Its native range spans northern temperate and subarctic regions. These include parts of Europe, Asia, and North America. It is native to Britain and Ireland. Wild plants grow in marshes, wet moorland, and raised bogs. They also occur at high altitudes. These wet habitats help explain its need for damp garden soil.

The plant forms a clump with a basal leaf rosette. Its heart-shaped leaves sit near the ground. The foliage falls away for winter. Upright stems rise above the leaves and carry white flowers. Each flower has a star-like shape and greenish veins. Flowers measure about 0.08 feet [0.025 metres] across. They appear in late spring and early summer. RHS describes plants about 0.66 feet [0.2 metres] tall. Its broader garden height range reaches 1.64 feet [0.5 metres]. Spread reaches about 0.33 feet [0.1 metres]. Plants take two to five years to reach full size.

Grow this species in full sun with deep, fertile soil. The soil must stay wet, but water should not stagnate. RHS lists both clay and loam as suitable soils. It accepts acid, neutral, and alkaline conditions. Plants can grow in exposed or sheltered sites. South-facing and west-facing positions suit them. RHS rates its hardiness as H7, for severe European winters. Plants For A Future gives USDA zones 4–8.

Its small size suits wet areas within a rock garden. RHS also suggests it for wildflower meadows. Plants For A Future lists it for bog gardens. Match these uses to its need for wet soil. Sow seed in containers during autumn to raise new plants. Divide established clumps in spring as another means of propagation. Cut plants back once flowering ends. Slugs and snails may cause damage. RHS reports few disease problems.

Plants For A Future records no known edible uses. It also lists no known hazards, though this does not establish safety. The same source records traditional medicinal uses for the whole plant. These include preparations for mouth sores, wounds, and eye care. Such records describe past uses rather than proof of benefit. It lists no other practical uses for this species.