If you've been hesitant to devote a bit of prime real estate in your garden to irises because of their short bloom season, these irises are for you.
A few years ago, horticulturists were hesitant to recommend reblooming irises because of their inferior blossoms and colors, but they've had to change their minds. The hybridizers that are developing these irises have outdone themselves, and the vigorous rebloomers are stealing the show.
Rebloomers typically bloom in spring as much as a week ahead of standard bearded irises, then when you least expect it they will surprise you with another flush of blooms in summer, and possibly again in fall. Gardeners in warm, dry climates may get as many as 4 reblooms from their irises.
Gardeners in USDA zones 4-10 can enjoy reblooming irises, with the exception of Florida and the Gulf Coast where the extreme humidity and high rainfall inhibits them. Plant them in an area where they will get at least 5 hours of sun a day. Reblooming Irises have an accelerated life cycle, so they will need a little more than standard irises. Feed them with a balanced fertilizer in spring and summer, and in warm climates you can feed them again in fall. Avoid fertilizers with a high nitrogen content, such as lawn fertilizer. An excess of nitrogen encourages the foliage and discourages the blooms.