Hypericum ascyron subsp. ascyron var. ascyron(great St. Johnswort, "Tomoeso")
Japanese name: トモエソウ（巴草） Scientific name:Hypericum ascyron subsp. ascyron var. ascyron
[Overview]
A perennial 0.5–1.3 m tall, found in sunny, slightly moist grasslands in the mountains.
It is hairless throughout.
The stem is erect and has 4 ridges.
The leaves are simple and decussate, lanceolate to oblong, 5–10 cm long and 1–3 cm wide, entire, with bases slightly clasping the stem.
The leaves have translucent dots.
Cymes at the stem tips bear 3–15 flowers.
The flowers are yellow with 5 petals, 5 cm across; the petals curve to one side, so the flower looks like a tomoe (comma-shaped swirl) when seen from above.
There are about 80 yellow stamens, divided into 5 bundles.
The style is 5-lobed.
Each flower withers in one day.
The fruit is a conical capsule, and the petals, stamens and style remain for a long time after flowering.
[Cultivation]
Propagate from seed or by division.
It prefers a sunny, well-drained place with good water retention, and dislikes dryness.
Water thoroughly when the soil surface dries.
In spring and autumn, apply slow-release fertilizer placed on the soil.
There are no particular pests or diseases.
[Notes]
The Japanese name comes from the shape of the flower.
