Clump-forming, tuberous perennial producing bright yellow flowers. Flowers 2-3cm across, each above a ruff of dissected, bright green leaves, in late winter and early spring. Quickly forms large colonies, particularly in alkaline soils. 5-8cm high by 5cm wide.

Fully to frost hardy. Grow in fertile, humus-rich soil that does not dry out in summer, in full sun or dappled light shade. Plant tubers 5cm deep in autumn. Eranthis tubers hate drying out. Like snowdrops (which are more tolerant), they need to be planted or transplanted "in the green", i.e. while the foliage is still fresh and the plants are in active growth. Prone to smuts. Slugs may eat the foliage.

Introduced to Britain as a garden plant in 1596. Now naturalised. First recorded in the wild in 1838.

The reason it was called Winter aconite and linked to Aconitum napellus as being just as poisonous is because plants were classified according to leaf shape in the 16th century. L'Obel's Stirpium adversaria nova (1571) and Plantarum seu stirpium historia (1576) (with a full page illustration on page 384 showing Eranthis and Aconitum together) along with the knowledge that related plants have similar medical properties caused the belief that Eranthis are as poisonous as Aconitum. They are both in Ranunculaceae and while Eranthis (like all Ranunculaceae) is toxic if eaten, it does not contain the same chemicals as Aconitum. Caesalpino (Ekphrasis, 1616) pointed out the error in classifying according to leaf shape and recommended flower shape. It contains pharmacologically interesting chemicals such as khellin, also present in Ammi visnaga. This is a vasodilator but quite toxic, but can be converted into khellin analogues such as sodium cromoglicate – used as a prophylaxis against asthma attacks – and amiodarone which has anti-arrhythmia actions so is used for atrial fibrillation and other arrhythmias. It is endangered and protected in the wild (Croatia) because of over-collecting for horticulture.

Gerard called it Aconitum hyemale, Winter Woolfes-bane, Hibernum or winter Aconite.

From the Greek 'er' for spring and 'anthos' for flower.

hyemalis- belonging to winter, 'hyems'.

Gerard wrote that it was 'counted to be very dangerous and deadly, hot and drie in the fourth degree' and reported to be good against scorpion bites.

Active principle- all parts especially tubers: eranthin A, B and other cardiac glycosides of the bufadienolide type.

Class 1b: Highly hazardous: cardiac glycosides inhibit Na+,K+-ATPase, substantial ingestion causes symptoms of cardiac glycoside poisoning, nausea, vomiting, diarrhoea, colics, bradycardia, disturbed vision, dyspnoea, cardiac arrest.

Highly toxic due to content of bufadienolide cardiac glycosides