Hemerocallis citrina aka Citron Day Lily

Hemerocallis citrina, or citron daylily, is a herbaceous perennial. It belongs to the Asphodelaceae family. Its native range spans the southern Russian Far East, China and Japan. Records also place it in Korea. It grows at forest edges, in grassland and on valley slopes. These habitats reach from near sea level into the mountains.

The plant forms a dense mound of arching, strap-shaped leaves. Its leaves die back at the end of the season. Garden plants stand about 3–4 feet (0.9–1.2 metres) tall. RHS gives an upper height of about 5 feet (1.5 metres). Clumps spread about 2–3.3 feet (0.6–1 metre) across. Leaves reach about 2.6–3.3 feet (0.8–1 metre) long. Tall, bare flower stalks rise above the leaf clump.

The lemon-yellow flowers have a trumpet shape and strong scent. Their sepals have brown tips. Flowers can measure about 0.5 feet (0.15 metres) across. They open in late afternoon or near sunset. Each bloom closes around mid-morning the next day. Many buds open in turn along several stalks. This gives one plant at least two weeks of bloom. Missouri Botanical Garden lists flowering from June to July. Chicago records a broader season from May through August. The flowers attract butterflies.

Grow this daylily in sun or part shade. It needs moist soil that drains well. It accepts a broad range of soils and pH levels. Sources describe it as easy to grow, with low upkeep. Its hardiness ratings are USDA zones 3–9 and UK H6. Plant clumps in borders, beds or larger groups. The arching leaves add texture after the blooms fade. Dense clumps can shade out weeds and serve as groundcover. Remove spent flowers and cut down stalks after flowering. Divide crowded clumps to keep them vigorous.

Serious problems are uncommon, but pests and diseases can occur. Aphids, thrips, mites and gall midge may attack plants. Slugs and snails can harm young leaves. Rust, bacterial rot and crown rot are further risks. PFAF lists young leaves, shoots, flowers, buds and roots as edible. It warns that large leaf servings may cause hallucinations. Its account leaves the safety of preparation unclear. RHS warns that this plant is toxic to cats. PFAF also records root-based folk remedies, not proven medical treatments. Dried leaves can supply fibre for cord and footwear.