“That flower looks just like an iris!” said a friend in disbelief, as she admired my perennial bed in late October a couple of years ago. And indeed, it was Iris St. Petersburg, a lovely tall bearded hybrid with violet-tinged white standards and falls, which had bloomed in spring (as most garden irises do) but then bloomed again over summer and fall. Reblooming—or remontant—irises such as this one are becoming increasingly popular as gardeners discover they can dramatically extend the flowering season of one of their favorite plant groups. Iris enthusiasts can also seek out species and cultivars that bloom naturally into the summer.
The iris is a well-known plant in the garden, prized for its linear form and colorful, uniquely structured flowers. But the taxonomy is complex, and its always good to preface a discussion about irises with a review of the jargon. In brief, iris flowers consist of three upright petals (standards) sitting atop three larger, usually pendent sepals (falls). The Iris genus is large, with over 250 species and many, many cultivars. Horticulturists divide all these into groups and subgroups according to general characteristics such as rootstock type (rhizomatous versus bulbous), place of origin, size, culture, and the presence or absence of colored hairs (beards) in the center of the falls.
The remontant irises are primarily hybrids of plants in the bearded iris group. Breeders have been churning them out like crazy lately: Over the past five years, hundreds of bearded rebloomers in all size categories have been registered with the American Iris Society. Some of these are all-season bloomers, and others bloom in the spring and then only once again in summer or fall. When choosing remontant irises, look for plants that are known to perform well in your part of the country. (Contact your local iris society for recommendations; see “Iris Resources.”) Thats because along with genetic factors, climate and culture are also important for reliable reblooming.
For gardeners interested in naturally late-blooming irises, choices abound. A number of bearded varieties bloom from early spring to early summer. Among beardless irises, many varieties in the Spuria subgroup bloom from late spring to midsummer. Some Siberian iris (Iris sibirica) and Japanese iris (I. ensata) selections bloom from mid-spring to early summer. Beardless southern blue flags (I. virginica) bloom into early summer. Bulbous irises in the Xiphium subgroup—including Dutch, Spanish, and English irises—flower from mid-spring to midsummer.
Few perennials bring as much reliable—not to mention brilliant and subtle—color to garden beds and borders as irises do. The remontant and late-blooming cultivars allow us to enjoy this color throughout much of the growing season. As with other garden irises, they range in size from tiny dwarfs to giants over four feet tall. The taller varieties serve well as background plants in perennial borders, while the small ones are perfect for edgings along the front of ornamental beds.
As for site considerations, there are irises to suit just about any soil type, from well-drained (bearded irises) to water-logged (Japanese irises). Xiphium, Pacific Coast, and Siberian irises thrive in soil that is kept moist. The miniature bulbous irises (Iris reticulata and I. danfordiae) require excellent drainage and are thus good candidates for rock gardens. Most irises prefer full sun or light shade and adapt to a wide range of temperature zones.
Following is a selection of some of my favorite remontant and later-flowering iris cultivars. The remontants all rebloom reliably in my garden in Missouri (USDA Zones 5 to 6), usually in late summer or fall, depending on the summer heat. Remontant cultivars are more productive than others, so give them a little extra water and fertilizer, especially after first bloom. Deadheading spent flowers also encourages repeat bloom. Most irises are best planted from midsummer to early autumn, but the plants can be installed in containers whenever the soil is workable.
A remontant tall bearded cultivar, Autumn Tryst grows 2½ to 3 feet tall and has showy, fragrant white flowers with rosy lavender edges. Hardy from Zones 3 to 10, it grows best in full sun and medium-moist soil. The first blooms appear in May. Autumn Tryst is a good choice for mixed perennial beds.
This remontant standard bearded dwarf (SDB) is hardy from Zones 3 to 10 and bears yellow flowers on 8- to 15-inch plants, first in the spring and then periodically through the season. Like other SDBs, it can tolerate more shade and a wider range of environmental conditions than other bearded irises. Baby Blessed is a good choice for edges of border beds.
Winner of the coveted Dykes Medal, this tall bearded iris grows 2½ to 3 feet tall and produces many flamingo-pink flowers with flaring falls in June. Hardy from Zones 3 to 9, it does best in full sun and medium-moist, well-draining soil. Beverly Sills is very effective when planted in masses.
As a gardening enthusiast I’m always looking to fill my garden with beautiful flowers that last all season long. One flower that often comes to mind for extended bloom time is the iris. With hundreds of varieties to choose from you can have irises blooming from early spring right through fall with the right selection and care.
In this article, I’ll provide an in-depth look at selecting, growing, and caring for iris that bloom all summer. Whether you’re new to irises or looking to expand your collection, you’ll find everything you need to know to have a rainbow of colors gracing your garden when other flowers have faded.
An Overview of Iris Seasonal Blooming Habits
While many iris bloom in spring or early summer, there are types that bloom outside of this typical season. Here’s a quick overview of when different iris bloom:
- Bearded iris – Mid to late spring bloom time, some rebloom in summer/fall
- Siberian iris – Spring to early summer bloom
- Japanese iris – Mid to late spring bloom
- Louisiana iris – Blooms late spring into summer
- Pacific Coast Hybrids – Bloom spring to summer
- Spuria iris – Midsummer blooming varieties available
- Reticulata iris – Very early spring bloomers
- Dutch iris – Blooms in late spring
As you can see, with thoughtful selection, it’s possible to have iris blooms for months! Next, let’s look at some of the best options for prolonged bloom.
Iris Varieties That Bloom All Summer
Here are some top picks for iris that will give you flowers from spring through fall
Reblooming Bearded Iris
Bearded iris are loved for their multicolored, ruffled blooms in spring. However, certain modern reblooming varieties will bloom again in late summer or fall. Some top choices include:
- Immortality – Lavender standards and white falls, reblooms reliably
- Autumn Echo – Yellow standards and red-violet falls, reblooms well
- Carnival Times – Standards of pinkish tan, copper falls, good rebloomer
- Reprise – Pale blue standards, darker blue falls, strong repeat bloomer
Louisiana Iris
Native to the Southern United States, Louisiana iris produce gorgeous, orchid-like blooms from late spring through summer. They thrive in hot, humid climates. Some recommended varieties include:
- Black Gamecock – Velvety purple-black blooms
- Cajun Sunrise – Sunset shades of orange, yellow, and pink
- Bold and Brassy – Brilliant golden yellow blooms
Pacific Coast Hybrids
Bred specifically for mild West Coast climates, these hybrids bloom vigorously from spring through summer. Some top choices are:
- Raspberry Ruffles – Ruffled blooms in raspberry-pink with tangerine beards
- Ocean Breeze – Silver-blue flowers with bright orange beards
- Point Cabrillo – Vibrant violet-blue blooms with orange beards
Growing Conditions for All-Summer Blooming Iris
To get the most out of your iris in terms of bloom time and performance, pay attention to their preferred growing conditions:
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Sunlight – All iris need at least 6 hours of direct sun daily. Morning sun is ideal, with some afternoon shade where possible.
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Soil – Well-drained soil enriched with compost is essential. Avoid overly wet soil.
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pH – Target a neutral to slightly acidic pH between 6.0-7.0. Irises don’t do well in very acidic or alkaline soils.
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Fertilizer – Use a balanced fertilizer in early spring. Too much nitrogen can inhibit flowering.
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Watering – Consistent moisture is important, but take care not to overwater.
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Hardiness Zones – Check zone ratings and choose varieties suited to your local climate.
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Location – Plant in an area protected from strong winds, which can damage stems and blooms.
Iris Care Tips for Optimal Blooming
Ongoing care and maintenance is vital to have your irises putting on their best floral display throughout the season. Here are some key tips:
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Deadhead spent blooms to encourage reblooming. Leave foliage intact until it browns.
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Divide congested clumps every 3-4 years to maintain vigor. Replant healthy rhizomes promptly.
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Watch for signs of diseases and pests like iris borers. Treat promptly to avoid spread.
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Remove any diseased or pest-damaged foliage. Keep beds free of weeds and debris.
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In very hot climates, mulch around iris to retain moisture and cool roots.
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Stake tall bearded iris varieties if needed to prevent flopping from wind/rain.
Designing With All-Summer Blooming Iris
With their sword-like foliage and bold blooms in a rainbow of hues, iris offer terrific visual impact in gardens. Here are some ideas for showcasing their beauty:
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Plant groups or drifts of the same variety for a cohesive look.
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Mix early and late bloomers together for ongoing color.
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Use taller bearded iris as background to shorter varieties in front.
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Contrast rich purple iris with bright yellows or whites for dramatic effect.
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Pair them with roses, peonies, daylilies, and other perennials that flower at different times.
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Mass plant Louisiana iris near ponds or water features for a lush, tropical feel.
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Use reblooming iris in containers for moveable color in fall.
Wrapping Up
With a strategic selection of different iris types and reblooming varieties suited to your climate, you can have a spectacular display of color in your garden from spring through fall. Pay attention to each variety’s growing needs, provide consistent care and maintenance, and you’ll be rewarded with months of exotic blooms and graceful foliage. A garden planted with diverse all-summer iris is a showstopper!
Iris fulva ‘Lois Yellow’ (copper iris)
A cultivar of our southern native copper iris, Lois Yellow is hardy from Zones 5 to 9 and grows two to three feet tall. It offers bright green, swordlike foliage and boasts showy yellow flowers from May to June. While best grown in full sun, it will tolerate partial shade, especially in the southern part of its range. The soil should be fertile, slightly acidic, and consistently moist to wet. It is another good choice for water gardens.
Growing over two feet tall, this Xiphium iris blooms from late spring to early summer. The graceful single flowers are a rich golden yellow. Hardy from Zones 5 to 8, Golden Harvest needs full sun and well-draining soil. If yellows not your color, choose a different cultivar. Modern Xiphium cultivars come in white, blue, and purple but otherwise look the same. Excellent in borders and containers, they also make great cut flowers.
This border bearded reblooming iris (border bearded irises are in a group known as Medians) is hardy in Zones 3 to 10 and grows 1½ to 2 feet tall. It blooms from May to June, producing intensely white standards overlaid with yellow, and yellow-edged white falls. Grow the plant in full sun and well-draining, medium-moist, humus-rich soil.
This tall bearded remontant iris is hardy from Zones 3 to 10 and typically grows three feet tall. The showy flowers feature golden-tan standards and falls, with cinnamon markings on the falls and white borders circling the beards. A good plant for sunny beds and borders, it grows best in full sun and organic, medium-wet, well-draining soil.
Iris siberica ‘Butter and Sugar’ (Siberian iris)
Hardy from Zones 3 to 8, this Siberian iris grows about 2¼ feet tall. Flowers appear from late spring to early summer sporting white standards and brilliant yellow falls. The plants thin, arching leaves add an ornamental grass–like texture to mixed borders. Butter and Sugar thrives in full sun to partial shade and medium-to-wet soil.
A tall bearded reblooming iris, this cultivar is hardy in Zones 3 to 10 and grows up to three feet tall. Its heavily ruffled standards and falls are brilliant white with a very slight tinge of violet. The falls have greenish-white centers, and the beards are pale lavender. St. Petersburg makes a bright accent in beds and borders of contrasting colors. Its best grown in full sun and fairly organic, well-draining, medium-moist soil.
Probably the best source of information on irises is the American Iris Society (AIS). For membership information, call 636-274-6149. The AISs website (www.irises.org) provides links to local and regional iris societies in the U.S., as well as specialty organizations, such as the Reblooming Iris Society (www.rebloomingiris.com; 903-463-4084). These societies can recommend local growers, but if you are unable to get your irises locally, following are a few mail-order sources.
Barbara Perry Lawton has served as editor and manager of publications for the Missouri Botanical Garden, president of the Garden Writers Association of America, and weekly garden columnist for the St. Louis Post-Dispatch. Her latest book is Hibiscus: Hardy and Tropical Plants for the Garden (Timber Press, 2004).
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FAQ
Are there irises that bloom all summer?
Iris Sibirica and Iris Germanica are superb summer iris species, flowering for months on end. A couple of Dutch Iris varieties can also flower in June and July.Feb 28, 2023
What is the most reliable reblooming iris?
Iris ‘Best Bet’ (Reblooming Bearded Iris)
‘Best Bet’ is a reliable, sturdy and vigorous grower – and understandably, a very popular reblooming iris. This early bearded iris usually produces 2 to 3 stems per plant early in the bloom season and then rewards us with new blooms in the fall.
How do I keep my iris blooming all summer?
Deadhead the iris frequently to encourage new flowering from buds growing further down on the stem. Let as much of the foliage remain on the plant as possible because it will continue to absorb the sun and feed the stems. Once flowering is over, cut the stalk down to the soil level but not into the rhizome or bulb.
How do you get reblooming iris to rebloom?
In climates with cold winters, you may see limited fall blooming. Reblooming Bearded Iris are heavy feeders, requiring more water and fertilizer for the extra boost to flower again. Be sure to deadhead faded flower spikes promptly after the first bloom, so plants will have time to form new flowers.
Do irises bloom in shade?
Many irises will grow in total shade, but they most likely won’t flower. The majority of irises will bloom in spring or summer. Dwarf varieties tend to bloom earlier in spring, with intermediate sizes blooming later spring, and taller bearded varieties blooming late spring and summer.
When do bearded irises rebloom?
While most irises flower in the spring, there are reblooming varieties of bearded iris, like ‘Immortality’, that can flower again in the early fall. To add splashes of color to my garden during the summer, I opt for a palette of purple, blue, yellow, white, and pink.
When do irises rebloom?
Summer: Dutch irises and English irises, types of bulbous irises in the Xiphium group, flower mid summer into early fall. They make great companions to summer perennials. Fall: Some reblooming bearded iris varieties will flower again in fall if conditions are right. This second bloom often occurs 8-10 weeks after the initial spring bloom time.
When do Dutch irises Bloom?
Details: Dutch irises are bulbous irises that flower mid summer into fall. Their strap-like leaves and elegant uniform blooms make them great cut flowers. Plant en masse for a bold summer display. Bloom Time: Mid summer to early fall
Do irises bloom in the summer?
Irises have beautiful flowers that make a backyard look great. Some bloom in the summer, while others shine in the late winter. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Irises are beautiful perennials that, depending on the type, can bloom between late winter and early fall.
How long do English irises Bloom?
English irises are known for their sweet fragrance. With so many different iris species and cultivars available, it’s possible to have irises in bloom for up to 6 months from early spring through fall: Plant early bloomers like dwarf iris and reticulata iris for the first flush of spring color.