Prunella vulgaris subsp. asiatica ("Utsubogusa")

Japanese name: ウツボグサ （靫草）
Scientific name: Prunella vulgaris subsp. asiatica

[Overview]
A perennial 15–40 cm tall that forms small colonies in mountain grasslands, hills and similar places.
After flowering it sends out short creeping stems bearing several pairs of leaves.
The stem is square in cross section, with hairs on the ridges.
Leaves are simple and opposite, oblong, 2–5 cm long, with a few low teeth on the margin.
The leaf stalk is 1–3 cm long.
At the stem tip it produces a dense flower spike 3–8 cm long made up of clustered verticillasters.
Many bracts grow in opposite pairs on the inflorescence, and each bract bears 3 flowers.
The flowers are purple, lipped, 1.5–2 cm long, and the upper lip is helmet-shaped.
After flowering, the inflorescence turns a blackish brown, as if withered.
The fruit is a schizocarp.

[Uses]
The flower spikes are used medicinally.

[Cultivation]
Propagate from seed or by division.
It prefers a sunny, airy, well-drained, fertile soil.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient.
Fertilizing is unnecessary because too much makes the plant leggy, but for potted plants a small amount of slow-release fertilizer with equal parts of the three components may be placed on the soil from before the buds open in spring until before flowering.
There are no particular pests or diseases.

[Notes]
The Japanese name compares the flower spike to a yukiko (a quiver for holding arrows).

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