When breeders crossed Iris sibirica, from Eurasia, and I. sanguinea, from Asia, the resulting hybrids became known as Siberian irises. Appearing in late spring, their beardless flowers come in shades of blue, lavender, magenta, pink, purple, yellow, and white. The blooms are borne on slender stems that reach 3 to 4 feet tall over grasslike leaves. The clumps spread 2 to 3 feet across.
Siberian irises grow in all Sunset Northwest climate zones 1a-7 and 17. In cold-winter areas, set out rhizomes in early spring or late summer. In milder areas, plant in fall. Give them neutral to acidic soil, regular water, and full sun (partial shade in hot-summer climates). Most nurseries carry at least a few Siberian irises. For a wider selection, order from Aitken's Salmon Creek Garden ( www.flowerfantasy.net or 360/573-4472) or Greer Gardens ( www.greergardens.com or 541/686-8266).