How to grow japanese iris

When to plant japanese iris

Plant new Japanese iris rhizomes in spring or fall, setting them about 1 to 2 inches deep and, unlike other irises, planting them vertically with the growing tip pointed up (NC State). Divide about every three years after flowering.

Japanese Iris is timed by season rather than your frost dates, so the planting calendar does not generate ZIP-specific dates for it. Check the cited sources below to fine-tune for your area.