Rhizomatous: Zones 5 through 10.
Bulbous: Zones 7 through 10.
Irises may be grown in colder areas if heavily mulched. To determine your zone, see the map in Plant Climate Zone Map.
Rhizomatous: Early summer.
Bulbous: Late spring through early summer.
Full sun.
Rhizomatous: Summer.
Bulbous: Fall.
Well drained. pH 6.0 to 7.5.
Fertilize with a balanced plant food according to label directions.
How much: Apply enough water to wet the soil to 1½ feet deep.
How often: Water when the soil 1 inch below the surface is just barely moist.
Mulch irises after the first hard fall frost. Divide rhizomatous iris clumps every 3 to 5 years.
