I’m always surprised to see my ‘Caesar’s Brother’ Siberian irises blooming. I would guess it’s been about 10 years since I planted them, and for quite a few years they didn’t bloom at all, or they sent up one or two measly flowers for the season.
It really wasn’t their fault. Irises take a few years to get established. Plus, I planted mine in a fairly shady location and the nearby astilbes took off like a shot each spring and buried them in foliage.
This year they’ve finally gotten the best of the astilbes and happily tower over them.
Siberian Irises are drought resistant, but they thrive in moist soil. And they are not affected by juglone, so you can safely plant them under Black Walnut trees. Black Walnuts release a phytotoxin called juglone which can kill, stunt or wilt many types of plants under and near its canopy.
‘Caesar’s Brother’ grows 36 inches tall in full sun to partial shade. The plants bloom in late spring and are hardy in zones 3-9.