Siberian iris is a tall, clumping plant with narrow, upright foliage. Plants grow best in moist, acidic soil but also tolerate drier soil. New for 2022: ‘Kaboom,’ with large, 6-inch double blue-violet flowers with gold and white sunburst blaze. Height 30 inches. Spread 24-36 inches. Zone 3. Plant in full sun or part shade.