Iris sibirica L.

Rhizomes compact, freely branching, forming dense clumps, 0.9–1.2 cm diam., covered with remnants of old leaves. Stems simple or 1–3-branched, hollow, 6–12 dm. Leaves dying back in winter, blade dark green, often tinged pink at base, 4–8 dm × 0.4–0.6 cm. Inflorescence units 3–5-flowered, lateral units 2–3-flowered; spathes brown, to 4 cm, narrow, papery, apex acute. Flowers: perianth light to dark blue-violet to white; floral tube with indistinct ribs, circular, ca. 1 cm; sepals flaring or curving downward apically, widely orbiculate, 5–7 × 2–2.5 cm, base abruptly attenuate into claw with two narrow flanges basally, signal white, semicircular, with dark violet veins basally; petals erect, narrowly elliptic-obovate, 4.5–5.5 × 1.5–1.8 cm; ovary roundly triangular, spindle-shaped, 1.5–2 cm; style pale blue, bluntly keeled, 4–5 cm, crests overlapping, triangular, margins crenate; stigmas tonguelike projections, triangular; pedicel 1–15 cm, unequal, later flowers in each spathe with longer pedicel. Capsules roundly triangular with low ridges at angles, 3–4.5 × 1–1.3 cm, smooth, apex with extremely short tip, opening only in upper 1/4–1/3 of capsule. Seeds in 2 rows per locule, dark brown, D-shaped, flattened, 5 × 3 mm, slightly roughened by small, rounded protuberances. 2n = 28.

It is a temperate plant. It is frost hardy. It grows in swamps and damp meadows. It can tolerate drier conditions. It can grow in full sun or light shade. The soil should be moist but not waterlogged. The soil should be rich in humus. it suits hardiness zones 4-9.

Plants can be grown from seed or by dividing clumps.