Iris flowers are a group of flowering plants that belong to the genus Iris, which includes around 300 species and thousands of cultivars. The name “Iris” comes from the Greek goddess of the rainbow, and the flowers are often associated with the colors of the rainbow, except for red. Iris is one of the most diverse and well-known groups of garden flowers in the world.
As a genus, irises have variation in their root systems, with rhizomatous and bulbous types represented. Leaves of all irises are lance-shaped, with variation in length, width and color. Flower shapes are divided into three main types, which include bearded, beardless and crested. Complex flower structures are made up of standards – upright petals – and falls – horizontal or downward-sloping petals.
The falls serve as landing platforms for pollinating insects, helping to guide them into the center of the flower. The standards are the three upright petals of the iris flower. They are usually narrower and more erect than the falls. The standards can be various colors, often contrasting with the falls. Some iris flowers have a “beard,” which is a row of fuzzy hairs on the falls, providing a landing place for pollinators.
Iris plants come in various sizes, ranging from 6 inches to 4 feet tall, and bloom in a multitude of colors, including shades of yellow, purple, white, and even black. They have a light, sweet scent that is similar to that of violets.
Depending on the species, irises are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 11. Dutch irises (Iris xiphium hybrids), hardy in USDA zones 6 through 9, are the most popular with florists, but many gardeners have even showier types available to them in their flowerbeds. Because buds on the same stem tend to open in succession, the flowers can last one week or longer in water, though the design of the bouquet will shift as the first blooms wither and new ones open.
History of Iris Flowers
The name “iris” comes from the Greek word for “rainbow,” reflecting the wide range of colors in which these flowers bloom. In Greek mythology, Iris was the messenger of the gods and the personification of the rainbow. She acted as a link between heaven and earth.
The use of iris as a garden plant dates back to 1469 B.C. The iris’s shape was the inspiration for the “fleur-de-lis” emblem, which was adapted by the powerful Frankish King Clovis I in 500 A.D., following his conversion to Christianity. The fleur-de-lis eventually became the recognized national symbol of France.
The iris was introduced to North America by early European settlers who brought the bulbs to the new world. Iris flower origins have been traced to Virginia, where bulbs were probably planted in the 1600’s.
The worldwide success story of the iris probably began around 1479 B.C., when King Thutmose III of Egypt had conquered Syria where irises grew in great profusion. Being a gardener as well as a warrior king, Thutmose ensured that irises should be immortalized in sculptures at the Temple of Amon at Karnak, as well as in the gardens of Egypt.
Classifications or Types of Iris Flowers
Bearded Irises (Iris germanica)
- Description: This is the most common type of iris, characterized by its “beard” or fuzzy hair on the falls (lower petals).
- Bloom Time: Late spring to early summer.
Examples
| Cultivar | Flower Color |
|---|---|
| ‘Autumn Tryst’ | White with rosy lavender edges |
| ‘Daughter of Stars’ | White |
| ‘Eleanor Roosevelt’ | Lavender |
| ‘Fall Spotlight’ | Yellow |
| ‘Holy Kosmoly’ | Blue |
| ‘Cantina’ | Purple |
| ‘Starship Enterprise’ | White with blue beards |
| ‘Black Swan’ | Black |
Siberian Irises (Iris sibirica)
- Description: These irises have slender, grass-like foliage and delicate flowers in shades of blue, purple, or white.
- Bloom Time: Late spring to early summer.
Examples
| Cultivar | Flower Color |
|---|---|
| ‘Blueberry Fair’ | Blue |
| ‘Blue Moon’ | Blue |
| ‘Butter and Sugar’ | White with yellow accents |
| ‘Caesar’s Brother’ | Purple |
| ‘Contrast in Styles’ | White with blue-green foliage |
| ‘Fond Kiss’ | White |
| ‘Granny Jean’ | White |
| ‘Gull’s Wing’ | White |
| ‘King of Kings’ | White |
| ‘Lavender Bounty’ | Purple |
| ‘Mission Bay’ | White |
| ‘Over in Gloryland’ | Blue |
| ‘Perry’s Blue’ | Blue |
| ‘Ruffled Velvet’ | Purple |
| ‘Shirley Pope’ | White |
| ‘Silver Edge’ | Blue with silver edges |
| ‘Sky Mirror’ | White |
| ‘Strawberry Fair’ | White |
| ‘Sultan’s Ruby’ | Red |
| ‘Super Ego’ | White |
| ‘White Swirl’ | White |
| ‘Wing on Wing’ | White |
Japanese Irises (Iris ensata)
- Description: Large, flat blooms with intricate patterns. They prefer wet conditions and are often found near water gardens.
- Bloom Time: Early to mid-summer.
Examples
| Cultivar | Flower Color |
|---|---|
| Kagami-jiro | Pure white |
| Mikawa-yatsuhashi | Deep purple with white markings |
| Okina-no-mai | Pink with red markings |
| Seiryu | Blue with white center |
| Shobu-hime | Lavender blue |
| Taiheiyo | Light blue with yellow markings |
| Utsukushi-no-hikari | Deep purple with gold markings |
| Yae-no-hikari | Double pink with white markings |
| Yukidaruma | White with green markings |
| Zuisho | Deep purple with ruffled petals |
Louisiana Irises (Iris hexagona)
- Description: These irises are native to the southern United States and thrive in wet, boggy conditions. They have large, showy flowers in shades of blue, purple, and white.
- Bloom Time: Spring to early summer.
Examples
| Cultivar | Flower Color |
|---|---|
| (Wild Species) | Light lavender white to rich pink to deep purple |
| (Wild Species) | Rarely white |
Dutch Irises (Iris x hollandica)
- Description: These are some of the earliest blooming. They have large, showy flowers in shades of blue, purple, yellow, and white. They are often used as cut flowers.
- Bloom Time: Spring.
Examples
| Cultivar | Flower Color |
|---|---|
| ‘Blue Magic’ | Blue |
| ‘Professor Blaauw’ | Blue |
| ‘Telstar’ | Yellow |
| ‘Apollo’ | White |
| ‘Casablanca’ | White |
| ‘Discovery’ | Purple |
| ‘Blue Diamond’ | Blue |
Reticulated Irises (Iris reticulata)
- Description: Small, early-blooming irises with netted bulbs. Ideal for rock gardens and containers.
- Bloom Time: Late winter to early spring.
Example
| Cultivar | Flower Color |
|---|---|
| Harmony | Purple with a golden blaze |
| Pixie | Deep violet-blue |
| Korzik | Purple with a white and yellow eye |
| Alida | Deep blue with a yellow blotch |
| Blue Magic | Intense blue |
| Mystic Charm | Purple with a contrasting yellow center |
| Cheerful | Yellow with a brown spot |
Spuria Irises (Iris spuria)
- Description: These tall irises have slender, upright stems and flowers in shades of blue, purple, or white.
- Bloom Time: Late spring to early summer.
Examples
| Cultivar | Flower Color |
|---|---|
| Adriatic Blue | Blue |
| Amber Crown | Yellow |
| Arctic Sun | Yellow |
| Chocolate Dreams | Brownish-red |
| Cinnamon Moon | Warm orange-brown |
| Gold Price | Golden yellow |
| Honey Mocha Lotta | Warm brown with gold highlights |
| Lavender Waves | Lavender |
| Sahara Sands | Golden yellow to sand |
Pacific Coast Irises (Iris douglasiana)
- Description: Native to the west coast of North America, these irises prefer milder climates and well-drained soil.
- Bloom Time: Spring.
Examples
| Cultivar | Flower Color |
|---|---|
| Wild Form | Purplish-red, light lavender, blue, creamy white, and variations |
| Pacific Coast Hybrids | Wide range of colors including soft pastels, mahogany, maroon, midnight purple, white, and yellow |
Yellow Flag Irises (Iris pseudacorus)
- Description: Typically found near wetlands, these irises have tall, sword-like leaves and bright yellow flowers.
- Bloom Time: Late spring to early summer.
Crested Irises (Iris cristata)
- Description: Small, ground-cover irises with a distinctive crest on the falls (lower petals). Ideal for shady areas.
- Bloom Time: Spring.
Examples
| Cultivar | Flower Color |
|---|---|
| Iris cristata | Pale lavender with white patch and yellow or orange crest |
| Iris cristata ‘Alba’ | White with yellow or orange crest |
| Iris cristata ‘Powder Blue Giant’ | Pale blue with darker blue signal and yellow crest |
Dwarf Bearded Irises (Iris pumila)
- Description: Miniature versions of bearded irises, suitable for rock gardens and borders.
- Bloom Time: Early spring.
Examples
| Cultivar | Flower Color |
|---|---|
| Thunderegg | Yellow and Purple |
| Volts | Pale Pink with Lavender Halo |
Roof Irises (Iris tectorum)
- Description: Traditionally grown on rooftops in Asia, these irises have broad leaves and light purple or white flowers.
- Bloom Time: Late spring.
Aril Iris (Iris subgenus Iris)
- Description: These irises have a distinctive, dark signal patch on the falls and are native to the Middle East and Central Asia.
- Bloom Time: Early Season
Intermediate Bearded Iris (Iris x)
- Description: These irises are a cross between tall bearded and dwarf bearded irises, with flowers in a wide range of colors and sizes.
- Bloom Time: Spring
Beardless Iris
These do not have a beard or crest on the falls. Examples include Japanese Iris, Louisiana Iris, Pacific Coast Natives, Siberian Iris, Spuria Iris hybrids, and Species Iris (wild irises).