Prunella grandiflora (large-flowered self-heal, "Tairin'utsubogusa")

Japanese name: タイリンウツボグサ （大輪靫草）
Scientific name: Prunella grandiflora

[Overview]
A perennial 15–30 cm tall that forms colonies, found in mountain pastures and wooded areas of Europe.
It produces stolons.
The stem is square in cross section.
The leaves are simple and opposite, ovate to lanceolate, about 10 cm long, with sparse low teeth along the margin.
A dense flower spike 5–7.5 cm long, made up of clustered verticillasters, is produced at the stem tip.
Numerous bracts are arranged in opposite pairs on the inflorescence.
The flowers are purple and lipped, 1 cm long, with a hooded upper lip.
The fruit is a schizocarp.

[Cultivation]
Propagate from seed, by division, or by stem cuttings.
It prefers sunny, well-ventilated, well-drained, fertile, moist soil.
For potted plants, water thoroughly when the soil surface dries; for plants in the ground, rainfall is sufficient.
Fertilizer is not necessary because too much makes it 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 spring before budding until before flowering.
There are no particular pests or diseases.

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