However, a surprise awaits the gardener seeking to extend iris' blooming season repeat blooming bearded iris, or fall-blooming iris. Although certainly not new to the garden, recent advances have made reblooming iris easier to obtain in myriad colors. New varieties rapidly entering the market make an iris aficionado's heart swoon with joy.
What Is a Reblooming Iris?
It's easiest to think about reblooming iris as 'repeat' blooming iris. Unlike traditional bearded iris, repeat blooming irises have been hybridized to produce plants that have the propensity, when given the right circumstances, to bloom again. The "right" circumstances vary, but generally speaking, all irises need bright, full sunlight (six or more hours a day), well-drained soil, and a temperate climate. Most reblooming iris fare well from gardening zone five and up, with little to no repeat blooms in gardening zones 3 to 4. The exception is the fragrant white-petal bearded iris known as 'Immortality', which has been known to produce repeat shows in colder climates.
Planting Repeat Blooming Iris
Like other types of iris, repeat blooming irises are generally planted in the late summer through the fall months. They may be sold in pots or as rhizomes. Always plant iris with the rhizome at or slightly above soil-level. The rhizome should be visible above the soil line. In very warm climates, you can sprinkle a little mulch or soil over the rhizome, but do not plant it too deeply. Space plants at least 20 inches apart.
Soil pH for repeat blooming iris is the same as for other types of iris, just slightly acidic or around 6.8. It's a good idea to have your soil tested at your local County Cooperative Extension office before planting any type of plants so you can add nutrients or adjust the pH accordingly.
Irises prefer rich, well-drained soil, but they can survive in almost any conditions. They do need full sun in order to bloom. If planted in dappled shade or full shade, they may grow foliage but fail to flower.
Keep iris well-watered until their roots are established. Mature plants shouldn't be watered too frequently; too much water can rot the rhizome. Wait to water mature iris plants until the top three inches or soil of soil are completely dried out.
Fertilizing Reblooming Iris
Because repeat or reblooming irises are investing a great deal of energy into a second blooming period, they benefit from added fertilizer. Fertilize them with a 5-20-10 or 5-10-10 fertilizer according to the package directions. Low nitrogen, high phosphorous fertilizer boosts blooms.
Repeat bloomers should be divided when the clumps reach maturity. You'll know when it's time to divide the clumps when the blooms dwindle. Sometimes this happens after three years, but depending on the variety and location, you may need to divide them every three, four or even five years.
Iris should be divided while dormant. Dormant period may be shorter for repeat blooming iris than for other types. You can thin repeat blooming iris in July, or after the fall blooming period. Replant rhizomes immediately and water the newly planted iris well until it established its roots.
Iris are named after the Greek goddess of the rainbow, and like the goddess, they come in a wide range of vivid hues. Repeat blooming irises are now available in bicolor varieties as well as single-color types. Some are more fragrant than others.
Varieties to consider include:
- 'Immortality' - perhaps the best- known repeat blooming iris, 'Immortality' features white ruffled petals. It blooms in mid-spring, and produces blooms again around September.
- 'Clarence' - a tall variety offering a light fragrance from flowers of creamy-white centers with violet-blue beards.
- 'Baby Blessed'- a dwarf bearded iris with creamy-golden yellow petals stippled with white. This one is great for borders and small spaces.
Using Reblooming Iris in the Garden
Tall varieties of repeat blooming iris make excellent perennial garden flowers. They can be added to cottage-style gardens, foundation plantings and cutting gardens as long as there is enough space for them and full sunlight. Dwarf irises make excellent rock garden or border plants. Consider iris foliage when designing your garden; the unique sword-like leaves offer texture as well as a soft, gray-green accent color spring, summer and fall.
For those who crave the hues and scents of iris each spring, repeat blooming iris satisfy the craving for beauty, color and fragrance throughout the growing season.
Thumbnail photo courtesy of Nancy Mason, picklebarrelhouseirisgarden