Eranthis hyemalis (winter aconite, "Kibanasetsubunso")

Japanese name: キバナセツブンソウ （黄花節分草）
Scientific name: Eranthis hyemalis

[Overview]
A perennial 10–15 cm tall, found in its native range on gravelly ground with limestone soil in forests.
It has an underground tuber.
The leaves are basal, divided into 3 segments to the base, and the segments are divided further.
The basal leaves have long petioles.
The basal leaves appear in autumn and the aboveground part dies back in early summer of the following year, making it one of the so-called spring ephemerals.
A single flower is borne at the stem tip.
At the base of the flower, 2 sessile bracts that are palmately divided grow in a whorl.
The flowers are 2–3 cm across and open upward, with 6 yellow, elliptical sepals that look like petals.
The petals are small and have changed into nectary-like structures that surround the stamens in a ring.
There are many stamens, and the anthers are yellow.
The fruit is a follicle.

[Cultivation]
Propagate from seed or by dividing the tubers.
When growing from seed, sow it fresh as soon as it is collected.
It also spreads readily from self-sown seed.
Soak the tubers in water overnight before planting.
It prefers fertile, well-drained soil in sun to partial shade.
It dislikes heat and dryness, so keep direct sunlight off the base of the plant.
For potted plants, move them to a cool shaded place from around the time the leaves die back in early summer, and keep them in the sun the rest of the time.
For plants in the ground, the area under deciduous trees is suitable.
For potted plants, water when the soil surface dries so that the plant does not run short of water during the growing season.
Even during dormancy, water enough to keep the soil from drying out completely.
For plants in the ground, rainfall is sufficient unless it becomes extremely dry.
Apply fertilizer placed on the soil once a month, or liquid fertilizer once a week, in spring and autumn.
There are no particular pests or diseases.

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