Linum lewisii aka Lewis's Flax

Linum lewisii is a soft-stemmed plant that lives for years. It belongs to the flax family, Linaceae. Common names include blue flax and prairie flax. Its native range spans Alaska to northern Mexico. It grows across the Great Plains and western North America. Wild plants grow in dry meadows and prairies. They also grow on foothills, mountains, and roadsides. People have brought it to some eastern states, where it now grows. Its species name honours explorer Meriwether Lewis.

Plants form mounds with several stems and a deep taproot. Garden height ranges from 2–3 feet [0.61–0.91 metres]. One account sets the height limit at 2 feet [0.61 metres]. Plants spread 1–2 feet [0.30–0.61 metres]. Thin green stems hold tough fibres. Young stems bear many leaves but lose most with age. The smooth, narrow leaves have plain edges. Their colour is grey-green or blue-grey. Leaves grow in turn along the stem. Lower leaves can seem to form whorls, or rings.

Blue flowers bloom from late spring through summer. Each forms a shallow cup with five petals. Flowers open near sunrise and drop their petals by noon. They form groups at the stem tips. Stems with buds bend down, then rise as flowers open. Plants may take up to three years to bloom. Round, pale yellow seed capsules then form. Each capsule splits into ten parts. It holds up to ten dark seeds. Bees seek nectar, while flies feed on pollen. Deer mice eat the seeds.

Grow blue flax in full sun where soil drains well. It suits dry, sandy, poor soil and withstands drought. It grows in loam and shallow, rocky ground too. Soil can be slightly acidic to moderately alkaline. Rich, wet ground can make stems flop and spread. It grows in USDA zones 4–8 and needs little care. Each plant lives just a few years but sheds seed freely. Sow from late autumn through early spring. Cut back half the top once blooms fade. This helps limit new plants from seed.

Blue flax suits sunny paths, borders, rock gardens, and pots. Flowers add colour and draw insects that pollinate them. Seed capsules suit dried displays too. Reports list no serious pests or diseases. Slugs, snails, and aphids may still cause harm. Indigenous peoples used stem fibres for baskets, mats, nets, and snowshoes. They used leaves and seeds in poultices, packs placed on skin as medicine. Cooked seeds are safe to eat and taste nutty. Never eat raw seeds. They hold compounds that can form cyanide. The plant can cause contact dermatitis, a skin rash from touch. Large amounts can poison livestock. This can cause severe trouble with breathing and death.