Aster tataricus (Tatarinow's aster, "Shion")

Japanese name: シオン （紫苑）
Scientific name: Aster tataricus

[Overview]
A perennial growing in damp grasslands in the mountains.
It reaches about 1–2 m in height, and the stem is erect and branches in the upper part.
The basal leaves are oblong, 6–13 cm wide, with teeth on the margin and sparse short hairs on both surfaces.
The basal leaves have long, winged petioles and wither at flowering time, but in cultivated plants they can reach 65 cm in length including the petiole.
The leaves on the lower part of the stem are simple and alternate, ovate to oblong, 20–35 cm long and 6–10 cm wide, with long petioles.
The leaves become smaller toward the top of the stem, narrowly oblong to lanceolate, and somewhat stalkless.
Many flower heads are borne in corymbs in the upper part of the stem.
The flower heads are about 3–3.5 cm across, with pale purple ray florets.
The involucre is hemispherical and 7 mm long, and the involucral bracts are in 3 rows.
The flower stalk is 1.5–5 cm and densely covered with short hairs.
The achene is obovate-oblong, 3 mm long, and hairy; the pappus is 6 mm long.

[History]
It has been cultivated as an ornamental since the Heian period.

[Uses]
The roots and rhizomes are used medicinally.

[Cultivation]
Propagate by division or stem cuttings.
It prefers well-drained, moderately moist soil and a place in sun to partial shade, out of the afternoon sun.
The roots are damaged in very wet places, but if it becomes too dry in summer, brown spots appear on the leaves and it may wither.
It is hardy, and if the environment suits it, it grows well even when left alone.
Apply slow-release chemical fertilizer around the base of the plant twice a year, in spring when the shoots emerge and after flowering.
Pests and diseases include root rot, powdery mildew, cutworms and aphids.

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