9 Types of Iris for the Flower Garden

The word iris comes from Greek word for rainbow, an apt term for a bloom that comes in such a large range of color combinations. The iris has been a valuable source of perfume ingredients and herbal medicines for centuries, but today's gardener treasures irises for their reliable spring performance and hardy vigor in the landscape. The iris is also a beautiful way to incorporate the symbol of faith and wisdom into your spring cut flower arrangements

There are different types of iris that will do well in almost any garden environment you might have except for extreme heat and dryness. Here are nine types of iris that are popular for North American gardens.

Gardening Tip

Most of the iris types require periodic division of the roots. The bearded types are prone to iris borer worms, and many gardeners lift the rhizomes nearly every year, cut away damaged sections, and replant the roots. This also offers a good time to propagate new plants. Siberian iris develop woody centers after a few years, creating bare spots at the center of the plant crown. These fibrous rhizomes should be lifted every three years or so, cut into pieces, and replanted. Other types of iris also benefit from periodic division.

  • 01 of 09

    Bearded Iris (Iris germanica cultivars)

    Bearded Iris

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    Bearded irises are the iconic plant familiar to nearly everyone. There are so-named not for the downward-facing petals, or falls on the blooms, but for the fuzzy beard that looks like the flower is sticking its tongue out. Virtually all bearded iris sold are named cultivars of I. germanica; the pure species is almost never grown.

    You can grow bearded irises exclusively and still achieve a garden with any color scheme you desire, and if you add some reblooming irises to your collection, you will enjoy that color show all season. The American Iris Society groups bearded iris into several subdivisions, including the tall bearded (more than 27 1/2 inches) and intermediate bearded (16 to 27 inches.

    When you've decided on one of the more than 60,000 cultivars available, plant it in late summer or early fall in full sun. Plant the rhizomes so that you can see them above the soil, for they thrive with good air circulation and sunshine. With good drainage and occasional dividing to prevent over-crowding, your irises can thrive for years. 

    Native Area: Southern Europe and Mediterranean; naturalized in many other locations

    USDA Growing Zones: 3–10

    Height: 2–3 feet

    Sun Exposure: Full sun

  • 02 of 09

    Dwarf Bearded Iris (Iris germanica cultivars)

    Dwarf Bearded Iris

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    The dwarf bearded iris group includes those cultivars of I. germanica that grow 8 to 15 inches tall. Another subdivision, the miniature dwarfs, are those less than 8 inches tall.

    What's not to love about these little powerhouses that illuminate your border and rock garden? Dwarf bearded iris varieties multiply quickly, so you can populate many areas of the garden with an investment in just a few plants. Some growers think these irises tolerate shade better than their standard cousins. 

    Native Area: Southern Europe and Mediterranean; naturalized in many other locations

    USDA Growing Zones: 3–10

    Height: 2–3 feet

    Sun Exposure: Full sun (tolerates part shade)

  • 03 of 09

    Dwarf Crested Iris (Iris crestata)

    Dwarf Crested Iris

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    Iris cristata, the native dwarf crested iris, has a special appeal to woodland gardeners, as it grows best in part shade. The 6-inch tall flowers appear from March to May, and will attract hummingbirds and bees to the garden. Provide an acidic soil to mirror the conditions of the pine groves where plants grow in the wild. 

    Like the bearded iris, this species spreads through rhizomes that can be divided to propagate new plants.

    Native Area: Eastern U.S.

    USDA Growing Zones: 3–9

    Height: 6–9 inches

    Sun Exposure: Part shade (tolerates full sun)

  • 04 of 09

    Species Irises (Iris spp.)

    Bamboo Iris
    Bamboo Iris

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    The Iris genus contains hundreds of flower species, many which are endemic to small geographic regions and therefore are not often cultivated. You may encounter these lesser-known varieties through small specialty nurseries or online plant forums where iris collectors propagate their own colonies of unique irises. Do not collect wild irises, which may be endangered in their native habitats.

    If you struggle to grow plants in an area with wet spring soils following the winter thaw, you can try the I. missouriensis. Gardeners in the South can grow I. confusa, also known as the bamboo iris, which prefers frost-free climates.

    Native Area: Various regions of North America

    USDA Growing Zones: Varies by species

    Height: Varies by species

    Sun Exposure: Varies by species; most are sun-lovers

    Continue to 5 of 9 below.
  • 05 of 09

    Dutch Iris (Iris [Dutch Hybrid Group])

    Macro of blossoming dutch iris apollo
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    Gardeners often overlook the small, simple flowers of Dutch iris like the 'Apollo' cultivar, but these diminutive plants serve as a good companion plants. Try growing them among early salad greens, which will obscure the fading foliage of the iris after they finish blooming. The flowers are usually yellow, blue, or white.

    Rather than growing from rhizomes, these are bulbous irises. Plant the bulbs deeply in the fall, at least 6 inches under the soil.

    Native Area: Nursery hybrids developed in Holland; parent species are native to Spain

    USDA Growing Zones: 6–9

    Height: 18 to 24 inches

    Sun Exposure: Full sun

  • 06 of 09

    Japanese Iris (Iris ensata)

    Japanese Iris

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    Iris ensata irises are not as well known as bearded irises or Dutch irises, but gardeners who want large irises should seek them out, as some varieties like 'Amethyst's Sister' and 'Freckled Peacock' routinely exceed 4 feet in height. 

    The Japanese iris demands constant moisture, full sunlight, and rich soil, so these plants would make a good addition to pond or stream side garden where the soil stays wet. 

    Native Area: Eastern Asia, Kazakhstan

    USDA Growing Zones: 4–9

    Height: 2–4 feet

    Sun Exposure: Full sun to part shade

  • 07 of 09

    Siberian Iris (Iris x)

    Siberian Iris

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    The Siberian irises is a subgroup in the American Iris Society's beardless division, which are lacking the fuzzy downturned "beards."  These are hybrid plants, derived mostly from two blue-flowered Asian species,  I. sibirica and I. sanguinea.

    Gardeners new to irises will love easy Siberian irises. They bloom slightly later than the bearded iris, providing a color bridge to the summer perennials. Unlike bearded iris, whose foliage becomes ratty and ugly after the plants finish blooming, Siberian iris maintains its clump of elegant waving foliage through the season, resembling an ornamental grass. This plant grows from very tough fibrous rhizomes that should be lifted and divided when the center of the crown becomes woody and non-productive.

    Unlike Japanese iris, the Siberian iris is fairly drought tolerant, and may succumb to crown rot if the soil stays too moist. Most Siberian iris flowers are blue, violet, or purple, and petals may be very ruffled. You will see Siberian irises described as diploid or tetraploid, which is in reference to the number of chromosomes in the plants. A diploid plant has two sets of chromosomes, but a tetraploid has four sets, resulting in stocky plants and large flowers with an excellent vase life. 

    Native Area: Nursery hybrids; parent species are native to northern Asia

    USDA Growing Zones: 3–9

    Height: 3–4 feet

    Sun Exposure: Full sun to part shade

  • 08 of 09

    Yellow Flag Iris (Iris pseudacorus)

    Yellow Flag Iris

    Mark Turner/Getty Images

    Iris pseudacorus is a vibrant and vigorous plant, sometimes to a fault. This wetland iris is invasive in many parts of the United States, so gardeners should cultivate the yellow flag iris responsibly in the landscape, and prevent it from escaping into nearby lakes and wild areas. Yellow flag iris spreads aggressively by rhizomes, and may be best controlled in a container water garden. 

    Native Area: Europe to western Siberia, Caucasus, northern Africa

    USDA Growing Zones: 5–9

    Height: 3–5 feet

    Sun Exposure: Full sun to part shade

    Continue to 9 of 9 below.
  • 09 of 09

    Louisiana Iris (Iris x)

    Louisiana Iris
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    The name "Louisiana iris" refers to a number of beardless hybrid irises derived from five different native species: I. fulva, I hexagona, I brevicaulis, I giganticaerulea, and I. nelsonii. Many of the hybrids are naturally occurring in their native boggy, swampy habitats, not the result of nursery development. As the name suggests, these parent species and their hybrids are most prevalent in the Gulf Coast area, and hence most of the Louisiana irises prefer the mild temperatures, moist spring weather, and slightly acidic sandy soil found in that area. However, some varieties are hardy as far north as zone 4. Like Japanese irises, these are water-loving plants.

    Native Area: Lower Midwest and Southern U.S.

    USDA Growing Zones: 4–9 (depends on variety)

    Height: 12 to 60 inches (depends on variety)

    Sun Exposure: Full sun to part shade

The American Iris Society also includes several other divisions and subdivisions of iris, in addition to the principal ones described here. As you develop your enthusiasm for irises, you may want to explore some of the more exotic and unique classifications.