Siberian irises are distinquished from Japanese irises because their foliage is thinner and more delicate, and the flowers are smaller and more upright.
I only have two Siberian Irises in my garden. I am hoping to add more this year, I love their no fuss style.
This one was already here when we bought this house. I think it is "Caesar's Brother".
Butter and Sugar
Siberian iris make wonderful landscape plants. The graceful flowers are carried above an elegant clump of grass-like, blue-green foliage which is attractive all season. Siberians bloom just after the bearded iris and just before the Louisianas and Japanese.
They can tolerate a wide range of soils, light exposures and moisture levels and are drought tolerant after they are established. They have almost no disease or pest problems. Ideal conditions are a sunny place with moist, rich, slightly acid soil.
They grow well next to pools or marshes and after the first frost their foliage turns a rich reddish-brown. Siberians can remain in place for years without division. When necessary, they should be moved in late summer, preferably September. Tetraploids have larger flowers and heavier foliage.
Japanese Irises
Japanese iris are a group of beardless iris which are the last to bloom, about a month after the tall bearded and Siberian iris.
The largest flowers of all iris, with lovely forms, colors and patterns, they require full sun, a heavy, acid soil and ample water. Mulch will help hold in water and reduce weeds.
Japanese iris are heavy feeders and an azalea-type fertilizer in the spring, just after bloom, is best. Keep the pH between 5.0 and 6.5. Japanese are generally prodigious growers so allow three or four feet between plants. Singles have three falls (3F), doubles have six (6F) and peony-type have nine or more (9F). The spectacular blooms are large, flat and four to eight inches across.
