Siberian Iris Blue King Actually from SE Europe, but super-hardy, Iris sibirica Blue King is a clump-forming, vigorous, rhizomatous, herbaceous perennial, with a very upright, but spreading habit – it needs space to spread out. The narrow, almost grassy leaves, 18”/45cm long, are grey-green to mid-green. In May and June, the branched stems carry up to five beautiful deep violet-blue flowers with lovely yellow and white markings on the ‘falls’. Siberian iris Blue King looks particularly good beside a pond or stream, but needs good drainage. Keep dead-heading to the base of the plant as the flowers go over, and divide every few years as the plants become congested and flower less freely. Site: Tolerates exposureSoil: Moderately fertile, humus-rich, moist, well-drained, neutral to slightly acid soilPosition: Full sun or partial shadeSeason of interest: SummerHardiness: Very hardyHeight: up to 4’ (1.2m) Spread: 1’2” (40cm) Photo by Enrico Blasutto and licensed under CC BY-SA 4.0.