How to Plant and Grow Reblooming Iris

They're not just for spring anymore. Reblooming irises light up your fall garden.

Reblooming irises aren't easy to distinguish from ordinary irises. Both types are perennials and flaunt sweet-scented fleurs-de-lis over a fan of leaves. Most irises cease blooming during summer, but rebloomers flourish during the warm months. With long growing seasons, reblooming irises can have three or four reblooms.

In general, the reliability of reblooming iris declines as you go farther north. Gardeners in Zones 3 and 4 may see little or no reblooming. In most types, the reblooming cycle is set off by cooler weather, so if your temperatures are tropical year-round, you may not see a second bloom. Also, some varieties won't start reblooming for a couple of years.

Where to Plant Reblooming Iris

Plant reblooming iris in a sunny spot that gets shade later in the day. Make sure they aren't overshadowed by other plants that can prevent them from getting the light they need. Reblooming iris does very well in its own spot, away from other flowers.

How and When to Plant Reblooming Iris

Plant reblooming iris rhizomes 1 to 2 feet apart, with the tops exposed and the roots beneath the soil. Plant in late summer or early fall, when nighttime temperatures are no lower than 50ºF, to give the roots plenty of time to get established before spring blooming. Once they're established, reblooming iris will grow very fast.

Reblooming Iris Care Tips

Because they're doing more work throughout the growing season, reblooming iris need more attention than regular varieties.

Light

Reblooming iris should be located where they get sun most of the time, with some shade later in the afternoon, especially in hot climates.

Soil and Water

Reblooming iris likes well-drained soils. If the soil in your garden is heavy, add coarse sand or humus to help with drainage. Reblooming iris needs fertile and slightly acidic soil.

Water every other week to keep the soil moist and prevent the plants from going dormant. However, this much water can cause regular irises to rot, so it's best to keep your rebloomers apart from your standard irises.

Temperature and Humidity

Since reblooming iris is hardy in Zones 3-9, it tolerates a range of temperatures. Keep them in moist soil and full sun, but make sure they get afternoon shade if the weather gets very hot in your area.

Fertilizer

Use a low-nitrogen fertilizer (one with a small first number, such as 5-10-20), following package directions. To prevent burning, don't allow the fertilizer to remain on the exposed rhizomes.
Feed the plants lightly in spring as growth starts, and again in September.

Pruning

After the first bloom, sometime in late May or June, trim flower stalks from plants but leave the foliage. Repeat the process after the subsequent flowering, and if there's another one, after it as well. Once the foliage dies back, cut back 3" from the base before winter.

Potting and Repotting Reblooming Iris

To pot reblooming iris, choose a container with drainage that's the right size for your plant. Dwarf plants need a 6 to 8 inch diameter pot, while tall plants need a 12" diameter pot. Add some gravel or stone to the bottom of the pot to assist with drainage. If planting rhizomes, plant as you would in your garden. Place the container in a bright, sunny spot.

Pests and Problems

Like other irises, rebloomers can fall prey to iris borers and various diseases. If you spot signs of decline, talk to your county extension service about steps you need to take.

How to Propagate Reblooming Iris

Reblooming irises grow faster than regular irises, so you'll need to divide them more often. To prevent overcrowding, divide reblooming iris every two to three years, but take only the outside rhizomes of the plant; leave the healthy older portions of the plant intact. Replant the small rhizomes 12 to 18 inches apart.

Types of Reblooming Iris

Although commonly called rebloomers, there are several types within this category, according to the Reblooming Iris Society:

  • "Rebloomers" (also called "remontants") are irises that produce two or more flushes of bloom each year.
  • "Cycle rebloomers" produce a spring crop of flowers, lie low during summer, and grow and flower again in the fall.
  • "Repeaters" produce new flowers soon after the first spring flush dies back, extending the bloom season to one to two months.
  • "All-season rebloomers" produce flowers irregularly throughout the season.

Most rebloomers are bearded iris, though some Siberian, Japanese, and other species offer this trait.

Below are some of the most reliable reblooming bearded iris. Note: the time of bloom refers to the first flowering.

'Autumn Bugler'

Early, tall (28 inches), purple

'Autumn Tryst'

Early to midseason, tall (34 inches), violet and white

'Baby Blessed'

Very early, dwarf (10 inches), light yellow

'Bountiful Harvest'

Early, tall (33 inches), violet and white

'Clarence'

Midseason, tall (35 inches), white and violet

'Corn Harvest'

Early to midseason, tall (30 inches), yellow

'Harvest of Memories'

Midseason, tall (40 inches), yellow

'Immortality'

Midseason, tall (30 inches), white

'Rebecca'

Midseason, tall (34 inches), rose pink

'Sugar Blues'

Mid to late, tall (36 inches), blue

Reblooming Iris Companion Plants

Allium

Hardy in Zones 4-9, their scent keeps animals away.

Tulips

Generally early- to mid-spring bloomers with many colors and varieties to choose from.

Peonies

This perennial with big-blooming flowers is a nice counterpoint to tall, narrow reblooming iris.

Frequently Asked Questions

  • Should I stake reblooming iris?

    Only stake these flowers if there are high winds in your location. Otherwise they stand strong on their own.

  • Why aren't my reblooming irises blooming?

    There are a few reasons your irises may not be blooming. Among others, they may be too crowded, they're planted too deep or they're not getting enough sun.

  • What's the best variety of reblooming iris to plant?

    One of the more dependable rebloomers is the white 'Immortality'. It first blooms in June, then returns in late summer.

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