When I was a kid it seemed that Siberian Iris were almost a nuisance. Flower gardeners were willing to part with them the same way veggie gardeners inflict zucchini on every passerby. The reason being they are so darned tough. Any plant that insists on living year after year after year will eventually need dividing. The rather plain varieties that I was given early on don't hold a candle to some of these more refined, fuller ruffled flowers that could almost pass for Japanese Iris in their form.
I've always thought of them as best suited for the north, but others view them as the best Iris for the south. Hey, there's something we can agree on! Plant in full sun in cooler locations, and give a bit of shade in hotter places. They like a moist but well drained soil, a bit on the acid side. They tend to flower with your late spring stars like peonies, oriental poppies and astilbes, just adding to the drama with their contrasting colors and textures. The bold upright foliage is an architectural feature all season long. The flowers also cut quite well, just cut when fully colored but not yet open.
Photos courtesy of Walters Gardens
Spread: 18.0-24.0 Inches
Hardiness Zones: 3,4,5,6,7,8,9
Foliage Color: Green shades
Sunlight: Full Sun (> 6 hrs. Direct Sun), Part Shade (4-6 hrs. Direct Sun)
Water Requirements: Average Water Needs, Consistent Water Needs
Soil Quality: Average Soil Quality
Soil Chemistry: Acidic Soil (pH < 7.0), Neutral Soil (pH = 7.0)
Bloomtime: Early Summer
'Blueberry Fair': 24.0-32.0 Inches
'Butter and Sugar': 28.0 Inches
'Cape Cod Boys': 27.0-32.0 Inches
'Skymirror': 32.0-35.0 Inches
'Swans in Flight': 33.0 Inches