Ranunculus sardous aka Hairy Buttercup

Ranunculus sardous is known as hairy buttercup or hairy crowfoot. It belongs to the buttercup family, Ranunculaceae. Its native range covers the Canary Islands and North Africa. It extends through Europe to the western Caucasus. The RHS lists it as native to Britain and Ireland. Its species name refers to Sardinia, where the naming collection originated.

This fast-growing weed lives mainly as a winter annual. Seeds sprout in autumn or winter. Growth then pauses until spring, though warm winter spells can restart it. Plants set seed in spring and die by early summer. Stems rise upright or lean upwards from a low, broad base. NC State gives heights of about 0.08–3 feet [0.025–0.91 metres]. Its listed spread is 0.25–0.67 feet [0.08–0.20 metres]. Dense hairs cover both the stems and leaves. Stems may be green, red, or brown and lack scent.

The green leaves grow alternately and have coarse teeth. Leaves near the base may have three lobes. Others divide into three leaflets in a palmate pattern. Leaf stalks often exceed 0.08 feet [0.025 metres] in length. Flowers appear from April to June. Each glossy yellow bloom forms a small cup with five petals. Five sepals bend back beneath the flower. Most petals measure less than 0.03 feet [0.008 metres] long. The flowers draw pollinators. Fruit heads hold up to 35 small achenes. These fruits are green before ripening and bear sparse hairs. Each measures about 0.007–0.010 feet [0.002–0.003 metres] long. They stay closed when ripe.

Hairy buttercup grows in sun or partial shade. It favours moist to wet soil and tolerates wet ground. It occurs in lawns, meadows, and naturalized areas. Its flowers offer some value to visiting pollinators. Yet its rapid growth can crowd out weak lawn grass. Damp soil and shade can make this problem worse. Mowing alone does little to check its low, broad growth. Dense, healthy turf helps limit its spread. NC State reports no major pest or disease problems.

This plant poses a poisoning risk rather than a food use. NC State rates its poison severity as low. It flags risks to people, cats, dogs, and horses. The listed toxic parts include roots, stems, leaves, flowers, fruits, and sap. They contain protoanemonin, an irritant. Poisoning may cause vomiting, diarrhoea, drooling, and mouth sores. Loss of appetite, depression, and an unsteady gait may also occur.