How To Grow Reblooming Iris
One of the most beautiful spring displays in your garden is the tall lush blooms of the iris. The only problem with these easy growing garden flowers is that they don't last very long. Well, if you love iris and want more of them, plant some reblooming iris in your garden. Reblooming iris will allow you to enjoy the showy display for longer than just a couple of weeks in the spring. Although not as well known as ordinary iris, reblooming iris have been around for a while. There are nearly 700 varieties of reblooming iris, 200 of which are hardy to Zone 5. They are slightly less likely to rebloom going up to Zone 3 or 4, although there are varieties (Immortality, for one) which will rebloom up to Zone 3.
Reblooming iris are almost as easy to grow as ordinary iris, but they do need a little extra effort. They need the same type of good, well-drained soil, but you should fertilize reblooming iris in spring and again after spring bloom. A complete analysis fertilizer like a 10-10-10 should be applied. You don't want the plants to go dormant, so they will need to be watered during dry weather. Another difference with ordinary iris is that although ordinary iris can be planted under deciduous trees since their sun requirements are primarily needed before blooming, rebloomers will need to have at least a half a day of sun all year.
Reblooming iris actually can be divided into several categories. "Rebloomers" are irises that will produce two or more flushes of bloom each year. "Cyle rebloomers" will have a spring flower crop then lie low all summer and grow and bloom again in the fall. "Repeaters" produce new flowers very soon after the first blooms die back and so extend the blooming season to one to two months. "All-season rebloomers" will bloom irregularly throughout the season.
It is important to keep these classifications in mind, although a lot of rebloomers are simply classified as rebloomers and not labeled by which type they are. Also, the reliability of rebloomers declines as you go farther north, but the reblooming cycle is set off by cooler weather, so where temperatures are tropical year round you may not have a second bloom. Some varieties may not start reblooming for a couple of years, so you will need to have patience and allow them to mature before enjoying that fall bloom. A good source of information for what types of reblooming iris will work for your area would be your local garden center or extension office.