Hemerocallis dumortieri aka Dumortier's Day Lily

Hemerocallis dumortieri is a perennial in the Asphodelaceae family. Common names include copper lily and Dumortier's daylily. Kew places its native range in Korea and possibly southern Jilin, China. Plants For A Future gives a wider range across temperate eastern Asia. Its account includes parts of Russia, China and Japan. It also records the plant in mountain meadows in Japan.

This compact plant forms clumps of narrow, upright leaves. The leaves die back for winter. RHS describes plants about 2 feet [0.6 metres] tall. Its size guide gives a range of 1.6–3.3 feet [0.5–1 metre]. Spread reaches about 1.6 feet [0.5 metres]. Plants take two to five years to reach full size. Red-orange buds open into deep orange flowers during summer. The blooms have a scent and reach 0.33 feet [0.1 metres] across.

Grow it in full sun for the best flower display. Shade can reduce bloom. It prefers fertile soil that stays moist but drains well. It also tolerates poor soil and heavy clay. Chalk, loam and sand suit it too. Soil may be acid, neutral or alkaline. Water during dry spells in spring and early summer to support flowering. RHS rates its hardiness H6, while Plants For A Future lists USDA zones 4–8.

Use it in flower beds, cottage gardens or meadow-style planting. RHS also lists coastal gardens and urban courtyards as suitable settings. Slowly spreading clumps can provide ground cover. Plants For A Future suggests spacing them about 1.5 feet [0.45 metres] apart. It records dried leaves as material for cord and footwear. Divide clumps in early spring or early autumn. Seeds can be sown in spring or autumn. Remove spent flower stems and dead leaves as needed.

Disease is not usually a major problem. Leaf spot, rust, and bacterial leaf or stem rot can occur. Pests include aphids, slugs, snails, gall midge, spider mites and thrips. Food uses need caution: RHS warns that this plant poisons cats. Plants For A Future records edible flowers, buds, roots, and very young leaves and shoots. It describes flowers and buds eaten raw or cooked. Older leaves and shoots become fibrous. The same source warns that large leaf portions may cause hallucinations. Its account of blanching does not explain a clear safety method. These food records should not be read as proof of safety.