Ranunculus arvensis aka Corn Buttercup

Ranunculus arvensis is also known as corn buttercup. It belongs to the buttercup family, Ranunculaceae. Its native range spans Europe, Central Asia, the Himalaya and North Africa. It grows in regions with a mild climate. Britain and Ireland form part of its native range. This annual was once a widespread weed in British cornfields. The RHS now reports only scattered sites in England and Scotland. It grows in farmed ground where the soil is rich in lime.

The plant grows in clumps and lives for one year. Deep cuts split its leaves into three or five narrow leaflets. Its small flowers have a soft, pale yellow hue. They bloom in late spring and early summer. Once the blooms fade, seeds form in spiny cases. These stand out and help you name the plant. Its many folk names include devil’s claws and hedgehog. The leaves are deciduous: they fall rather than stay green.

Grow corn buttercup in full sun, in neutral or alkaline soil. It accepts chalk, loam, sand and clay, even heavy clay. The soil must drain well but stay moist during growth. It suits both open sites and spots with shelter. The RHS suggests sites that face south or west. It gives the plant a UK hardiness rating of H5. This covers winter lows of 5 to 14°F [−15 to −10°C]. Grow new plants from seed. There is no need to prune it.

Corn buttercup suits informal beds, cottage gardens and plots for wildlife. Bees and butterflies come to the flowers for nectar. Birds eat the seeds, so they too gain from this plant. Pale blooms and spiny seed cases add interest at different stages. The RHS reports few usual pest or disease problems. Its past as a crop weed still matters in farmed ground. But this does not mean it is still widespread in Britain.

Do not eat this plant; there are no recorded food uses. All fresh parts are poisonous, and the sap can blister skin. Eating or touching it can harm both people and pets. Wear gloves and clothes that guard your skin when handling it. PFAF records its use to treat fever, gout and asthma. Those records do not show that home treatment is safe. Gardeners must note this, since the plant is toxic. PFAF lists no other uses beyond these records of medical use.