Linum catharticum aka Bitter Flax

Linum catharticum is a small annual in the flax family, Linaceae. Its common names include fairy flax, dwarf flax and purging flax. It is native to Britain and Ireland. Its wider native range spans Europe and reaches the Caucasus and Iran. The listed distribution also includes Morocco. In the wild, it grows in grassland, dunes and moors. It occurs most often on grassland over lime-rich ground.

This plant reaches about 1 foot [0.3 metres] in height. Its annual life cycle makes it a short-lived garden plant. It flowers from June to September, spanning summer into early autumn. Each flower has both male and female organs. Flies pollinate the flowers, and the plant is also self-fertile. It therefore does not depend on a separate plant for fertilisation. The supplied species records give no leaf or fruit details.

Grow fairy flax in full sun, away from shade. It prefers a sheltered site with soil that drains well. Light sandy soil and medium loam both suit it. The soil should contain humus and have a moderate nutrient level. It prefers moist ground, despite its need for good drainage. It accepts mildly acid, neutral and alkaline soil. It can also grow where the soil is very alkaline. These needs make drainage and light key factors when choosing a bed.

The recorded garden setting is a cultivated bed. Its low height places its flowers close to ground level. Its wild habitats offer context for choosing a garden site. However, the cultivation record calls for moisture rather than dry soil. Sow seed directly where the plants will grow in early spring. The sources give no hardiness rating or mature width. They also provide no species-specific account of pests or diseases. Plants For A Future does not flag it as weedy.

No edible use is known, and large doses are poisonous. Purging flax has a history of use as a laxative. Past herbal uses also included liver complaints and muscular rheumatism. The whole herb was used to promote urination and cause vomiting. It now has little use in modern herbal practice. These records describe past uses, not evidence of safe home treatment. Plants For A Future lists no other uses.