Helleborus niger (hellebores)

Japanese name: クリスマスローズ
Scientific name: Helleborus niger

[Overview]
An evergreen perennial about 20 cm tall.
The leaves are basal, pedately divided into 7–9 lobes, and leathery; the lobes are oblong with serrations on the upper half of the margin.
The leaf stalks are long.
The flowers are borne 2–3 to a cyme.
What look like 5 petals are actually sepals, white and sometimes tinged with pale reddish purple on the back.
The sepals turn green when the stamens ripen and the anthers open.
The true petals have changed into small tubular nectaries that surround the many stamens in a ring.
The fruit is a follicle, and the seeds have an appendage (elaiosome) along the raphe that ants and similar insects like, so the seeds are dispersed by ants.
The whole plant is poisonous and is said to contain cardiac glycosides with a burning taste; care is needed because the sap can cause inflammation if it gets on the skin.

[Cultivation]
Propagate by division or from seed.
A fertile, well-drained site that is sunny from autumn to spring and shaded in summer is suitable.
It grows from autumn to spring and becomes half dormant during hot, humid periods.
Excess moisture rots the roots, so keep it slightly on the dry side throughout the year. Water when the soil surface dries, but during dormancy water sparingly, only to the extent that the soil does not become extremely dry.
Fertilize only from winter to spring, giving liquid fertilizer once every 10 days.
Care is needed because frost and cold wind damage the leaves.
Unless you want to collect seed, pinch off the flowers at the neck after flowering so as not to tire the plant.
In early winter, when new leaves emerge, cut the old leaves off at the base.
Diseases and pests include gray mold and black spot.

[Notes]
The Japanese name comes from the fact that it blooms around Christmas. Lenten roses (Haru-zaki Christmas rose) and their hybrids are also sold under this name.

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