9 Top Types of Iris for the Flower Garden

Bearded Iris (Iris germanica cultivars)

The bearded iris, the iconic plant familiar to nearly everyone, is named not for its downward-facing petals but for the fuzzy beard that looks like it's sticking out its tongue. Virtually all bearded irises sold are cultivars of Iris germanica; the pure species is rarely 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, you'll enjoy a color show all season. The American Iris Society groups bearded iris into several subdivisions, including the tall bearded (higher than 27.5 inches) and intermediate bearded (16–27 inches).

When you've chosen 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 because 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 the Mediterranean; naturalized in many other locations
• USDA Growing Zones: 3a–10b
• Height: 2–3 feet
• Sun Exposure: Full sun

Dwarf Bearded Iris (Iris germanica cultivars)

The dwarf bearded iris group includes those cultivars of I. germanica that grow 8–15 inches high. Another subdivision, the miniature dwarfs, grows less than 8 inches high. What's not to love about these little powerhouses that illuminate your border garden 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: 3a–10b
• Height: 2–3 feet
• Sun Exposure: Full sun; tolerates partial shade

Dwarf Crested Iris (Iris crestata)

I. cristata, the native dwarf crested iris, has a special appeal to woodland gardeners, as it grows best in part shade. The 6-inch-high flowers appear from March to May and will attract hummingbirds and bees to the garden. Provide acidic soil to mirror the conditions of the pine groves where these 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 United States
• USDA Growing Zones: 3a–9a
• Height: 6–9 inches
• Sun Exposure: Partial shade; tolerates full sun

Species Irises (Iris spp.)

The Iris genus contains hundreds of species, many of which are endemic to small geographic regions and therefore not often cultivated. You may encounter these lesser-known varieties through small specialty nurseries or online plant forums where iris collectors propagate colonies of unique irises. Don't 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, try I. missouriensis. Gardeners in the South should try I. confusa, also known as the bamboo iris, prefers frost-free climates and growing conditions similar to azaleas.

• Native Area: North America
• USDA Growing Zones: Varies by species
• Height: Varies by species
• Sun Exposure: Varies by species; most prefer sun

Dutch Iris (Iris hollandica)

Gardeners often overlook the small, simple flowers of Dutch irises, like the 'Apollo' cultivar, but these diminutive varieties serve as 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.

• Native Area: Nursery hybrids developed in Holland; parent species are native to Spain and Morocco
• USDA Growing Zones: 6–9
• Height: 18–24 inches
• Sun Exposure: Full sun

Japanese Iris (Iris ensata)

I. ensata, or the Japanese iris, isn't as well known as the bearded iris or Dutch iris, but gardeners who want large blooms should seek them out. Some varieties, like 'Amethyst's Sister' and 'Freckled Peacock,' routinely exceed four feet in height. The Japanese iris demands constant moisture, full sunlight, and rich soil, so these plants would make a good addition to a pond- or stream-side garden where the soil stays wet.

• Native Area: Eastern Asia, Kazakhstan
• USDA Growing Zones: 4a–9a
• Height: 2–4 feet
• Sun Exposure: Full sun to partial shade

Siberian Iris (Iris sibirica)

The Siberian iris is a subgroup in the American Iris Society's beardless division, which lack the fuzzy, downturned "beards." These are hybrids, 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 summer perennials. Unlike bearded iris, whose foliage becomes ratty and ugly after the plants finish blooming, Siberian iris maintains its 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 nonproductive.

Unlike Japanese iris, the Siberian iris is fairly drought tolerant and may succumb to crown rot if the soil stays too moist. Most are blue, violet, or purple, and petals may be ruffled. Siberian irises are described as diploid or tetraploid. 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: 3a–9a
• Height: 3–4 feet
• Sun Exposure: Full sun to partial shade

Yellow Flag Iris (Iris pseudacorus)

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

Native Area: Europe to western Siberia; Caucasus; northern Africa
USDA Growing Zones: 5a–9a
Height: 3–5 feet
Sun Exposure: Full sun to partial shade

Louisiana Iris (Iris x)

The name "Louisiana iris" refers to several beardless hybrids derived from five 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 and aren't the result of nursery development. As the name suggests, these parent species and their hybrids are most prevalent in the Gulf Coast area. Hence, most 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, Southern U.S.
• USDA Growing Zones: 4b–9a (varies by hybrid)
• Height: 12–60 inches (varies by hybrid)
• Sun Exposure: Full sun to partial shade