Eranthis is a tuberous genus in the Ranunculaceae family from Europe and Asia. The species have yellow or white cup-shaped flowers over a whorl of dissected leaves. They all need cool growing conditions as they are woodland or mountain plants. They are good choices for naturalizing in semi-shade where they will not be disturbed. The Scottish Rock Garden Society has devoted the January 2014 e-magazine to this genus.
Eranthis cilicica and Eranthis hyemalis are sometimes considered to be conspecific, but as garden plants they are distinct. E. cilicica blooms after E. hyemalis has finished. Photographed by Jim McKenney in his USDA zone 7 Maryland garden where E. cilicica seems much more sensitive to summer moisture than E. hyemalis.
Eranthis hyemalis is commonly known as Winter Aconite. Carolyn Walker has written an informative blog post with many photos about this species. It is a native of European woods with yellow flowers. It is common to see spectacular patches where they have been left alone to spread through areas covered with stone chippings. Flowering occurs early in the year, only just later than the snowdrops. In his magnum work on seed germination (see HowToGrowBulbsFromSeed) Norman Deno picked this species as an exemplar of seed that will not stand dry storage, requires a warm period to break down germination inhibiting chemicals and will germinate at low temperatures (40 °F). It will only keep growing as long as it is cold and since success depends on keeping seedlings growing as long as possible it is wise to avoid exposing plant pots to the sun. Photos by John Lonsdale.
Photos by David Pilling of plants grown from seed that was supplied dry (about three years from seed to flower) growing in a 5 inch plant pot. Photo 1 shows emerging flowers; photo 4 is of a dormant tuber in May; results from planting dried tubers are often poor. Photo 5 of a seed pod photo was taken on the 21st March 2013 and photo 6 on the 10th May 2013 (10 mm grid).
Photographs of the resulting seed on a 1 mm grid; after collection the seed was kept moist at outdoors temperatures and began to germinate at the end of December 2013.
Eranthis hyemalis 'Aurantiaca' is a cultivar with flowers that are more golden than yellow. Photos from John Lonsdale.
Eranthis hyemalis 'Gothenburg' is a semi double cultivar. Photos from John Lonsdale.
Eranthis pinnatifida is a native of Japan where it is found in mountain woods. It has small white flowers. Photos by John Lonsdale.
Eranthis stellata is from China, North Korea and eastern Russia where it is found in forests and woodlands. It blooms early spring. Photos by John Lonsdale.
Eranthis x tubergenii is the name given for hybrids of Eranthis hyemalis and Eranthis cilicica. These two species hybridize to produce vigorous sterile plants with large flowers. The first four photos are from John Lonsdale and the last two are from Rodger Whitlock.