Everyone loves Dutch iris, but I’d like to draw your attention to their smaller, humbler, but undeniably more useful cousins, the Siberian iris.
Bagged Siberian iris roots for cheap. They start well this way
I’ve grown Iris siberica in both USDA zone 5 (central Illinois) and USDA zone 8 (Puget Sound area). They survived in both places, though their site in Illinois was hot, dry, and had poor soil. In that location, while their foliage came up, they didn’t bloom. Here on the shores of Puget Sound, in a bed of amended topsoil with clay beneath, they bloom like bonkers. This leads me to conclude that, while they’re indifferent to winter cold and summer heat, they do need some feeding to be happy.
Two colors of blooms in early June
The primary virtue of everything in my sunny perennial borders is that it produces gorgeous flowers, which Siberian iris undoubtedly does. They’re available in shades of blue, purple, yellow and white. Siberian iris provides a secondary and almost larger benefit, though, in its persistent foliage. The leaves are green and strappy, somewhat above knee height, and persist through the summer until cold temperatures turn them golden. Eventually they collapse onto the ground and then should be cleaned up, but in the meantime, they provide a spectacular backdrop for other things and have a knack for filling in gaps.
The grassy green foliage persists throughout the growing season, making a good backdrop for other plants. Second-year plant seen here on the far right
Every Siberian iris I have was grown from a bagged root. Above in this post were some I bought at my local major retailer. This was the first time I’ve seen Siberian iris roots there though, and I do pay attention, so if you don’t see them don’t be distressed. Turn to online sources. My bagged-root source of choice is Bulbs Direct, which has the virtue of being cheap and offering a large selection. Their drawbacks are that they have a confined sales season, some roots arrive dead and growing mold, and they have persistent problems with correctly labeling the varieties of their plants. That’s how I ended up with the two shades of purple shown above. For the price they’re asking I’m more than willing to swallow these failings, though, and I’ve always received prompt and friendly replies to inquiries.
Golden Siberian iris foliage playing backdrop to spent sedum heads in early November
Once established in a happy place Siberian iris is almost care-free. As I said the foliage will need to be cut short after it has collapsed in late fall or early winter; some other perennials stay upright and have winter interest but these just turn into a soggy mess. Do manure them in the fall and mulch them in the spring, just like you would anything else (riiiiight?). Other than that, once they’re in place, don’t mess with them. They dislike being moved and will probably sulk the next year. They’re far less prone to disease than Dutch iris and far less picky about their spot than some of the water-loving irises, though, and they are the only iris Piet Oudolf recommends for naturalistic planting.