Iris

( EYE - riss )

At-A-Glance Information

Iris is a genus of highly variable flowering perennials that grow from corms and rhizomes. Flowers are often fragrant, and vary widely in color, though they are all showy and will add immediate interest to your garden. Irises are named for the Greek rainbow goddess and are the inspiration behind the fleur-de-lis emblem. Grow Irises in containers, mixed beds and borders, or as specimens in the landscape. Take care when planting Irises in the landscape, as all plant parts are toxic to humans and pets if ingested.

Iris Subgenera, Species and Varietals

The genus Iris is a member of the plant family Iridaceae and includes over 300 species. Iris plants vary widely in flower colors and forms and they are generally grouped into three categories: bearded, beardless, and crested. To find your zone, click here: Zone Map.

Iris acutiloba
This species is native to the Middle East and Mediterranean, and is considered a dwarf species, reaching up to 10 inches tall. It has a creeping habit, forming clumps over time. These plants produce flowers that are cream-white and heavily veined with dark purple-red to brown. Petals have dark spots on them.

Iris adriatica
This species grows from rhizome roots and is native to the Dalmatia region of Croatia. Leaves are short and green, and stems and flowers are small. Blooms vary in color from light yellow to purple or violet. Individual plants reach up to between 12 and 18 inches tall at maturity.

Iris albertii
Native to central Asia, this species of Iris prefers to grow in grassy landscapes. It reaches up to between 16 and 20 inches tall when mature, and produces purple flowers with white to pale blue beards. Blooms last for 2-3 weeks in late springtime before fading. Foliage is blue-green.

Iris albicans (Cemetery Iris, White Cemetery Iris, White Flag Iris)
This species is native to the Middle East and northern Africa, where it was historically planted on graves in Muslim regions. Plants reach up to 2 feet tall, and produce strappy blue-green foliage and white flowers with cream-yellow beards. Spreads via rhizome roots and does not produce seeds.

Iris aphylla (Leafless Iris, Table Iris, Stool Iris)
These plants are native to Eurasia, and produce bright green grassy foliage that dies back in the wintertime. Slender flowering stems are topped with violet to pinkish-purple blooms in spring and early summertime. Individual plants reach up to between 3 and 12 inches tall when mature and in bloom.

Iris arenaria (Sandy Iris, Sand Iris)
These pale to golden yellow flowers are native to sandy areas in central Europe. They have long, flattened green leaves and reach about 10 inches tall when mature and in bloom. Stems hold between one and two flowers, which are present from April through May. Blooms are vanilla-scented. The species is considered to be endangered.

Iris atrofusca (Judean Iris, Gilead Iris)
These plants are native to Israel, Palestine, and Jordan. They form long, thick flowering stems topped with maroon to purple-brown fragrant flowers. Beard is brown-black and thick. Plants reach up to 18 inches tall.

Iris atropurpurea (Coastal Iris, Purple Iris)
Native to Israel, this species blooms between the months of February and March, producing stems topped with maroon to deep red flowers. These plants need very dry conditions to thrive, and do well in rock gardens. Leaves are linear and green, almost grass-like.

Iris aucheri (Aucher-Eloy Iris)
This species reaches up to 10 inches tall and is considered a dwarf Iris. It produces several flowers in late winter to early springtime, which have a violet-like scent to them. The species is native to western Asia and is hardy down to 5 degrees Fahrenheit.

Iris bismarckiana (Nazareth Iris)
These plants are native to Israel, Lebanon, Jordan, and Syria, and flower between March and April. They produce green foliage and flowers that vary in color from pale yellow-cream to white. They are covered in red-brown markings and spots. This species thrives in dry conditions.

Iris bracteata (Siskiyou Iris)
Endemic to the Klamath Mountains in California and Oregon, these plants produce cream-colored to yellow flowers. Blooms typically will have dark purple to brown veining. Flowering stems can hold one or two flowers.

Iris brevicaulis (Zigzag Iris)
Native to North America, these plants produce green, glossy leaves and a long, zig-zagged stem that holds between 3 and 6 flowers. Blooms range in color from violet to blue, with yellow-whitish centers.

Iris confusa (Bamboo Iris)
These white to soft lavender Iris flowers has yellow-orange crests and purple dots. Stems are bamboo-like, hence the common name of the species. Blooms are present in April and May.

Iris cycloglossa (Afghani Iris)
This species is native to Afghanistan and reaches up to 12 inches tall when mature and in bloom. Flowers are violet to blue and white, typically with purple to blue veining and yellowish centers.

Iris douglasiana (Douglas Iris)
These purple flowers are native to California and Oregon, where they grow in low elevations in coastal grassland areas. Blooms are present from April through June, and sit atop flowering stems that range from 6 to 32 inches tall.

Iris ensata (Japanese Iris, Japanese Water Iris, Hanashobu)
Native to Japan, Korea, China, and Russia, these widely cultivated ornamental plants reach up to 31 inches tall when mature and in bloom. Flowers are white with purple centers and yellow centers and dark purple veining.

Iris flavescens (Lemonyellow Iris)
This species is native to Pennsylvania in the United States, and produces green, strappy foliage. Blooms appear in spring or summer and are light lemon-yellow, sometimes with white and maroon markings on outer petals.

Iris fulva (Copper Iris)
This species of Iris is native to the southern and central United States, and produces copper to reddish flowers. Leaves are bright green and linear. Individual plants form clumps to 1-2 feet wide over time, and reach up to over three feet tall when mature and in bloom. Flowers bloom between the months of April and June.

Iris furcata (Forked Iris, Fork Iris, Forked Stemmed Iris)
These perennial rhizomatous plants are native to the Caucasus Mountains in Moldovia and Ukraine. Plants form narrow, sword-shaped green foliage and slender stems that branch. Blooms are reddish-purple, purple, or pinkish-purple, and bloom in late spring and summer.

Iris x germanica (German Bearded Iris)
This hybrid species produces plants that grow to reach up to 48 inches tall and 12 inches wide. They bloom from mid to late spring, and there are many cultivars with varying flower colors and compositions.

'Amas'

'Black Prince'

'Crimson King'

'Dominion'

'Dusky Challenger'

'Florentina'

''Germanica Alba'

'Gypsy Queen'

'Kharput'

'Titan's Glory'

Iris giganticaerulea (Giant Blue Iris)
These plants are native to north America, and have long, bright green leaves. Very tall flowering stems are topped with fragrant flowers in shades of blue (sometimes white). Individual plants reach up to 71 inches tall when mature and in bloom.

Iris hartwegii (Foothill Iris, Rainbow Iris, Sierra Iris, Hartweg's Iris)
These plants are native to California, where they grow in mountain slopes along the Sierras. They produce between 1 and 3 flowers per stem. Blooms are purple, yellow, or almost white with lavender veining.

Iris haynei (Gilboa Iris)
This species is native to shrublands and mountainous areas in Israel and Palestine's Gilboa mountain. It produces smooth linear green leaves and blooms between March and April. Flowers are deep purple, violet, brown-purple

Iris hermona (Golan Iris)
These perennials are native to Israel and Syria and produce linear green leaves and bi-colored flowers in white and brown-maroon. Signal patches are almost black. Individual plants reach up to between 12 and 20 inches tall at maturity.

Iris hookeriana
These plants are native to the Himalayan mountain range in India and Pakistan. They produce long, narrow green foliage and tall flowering stems. Blooms range in color from blue to purple and lilac, mottled with darker colors and with white and yellow beards.

Iris spp. Hybrids and Cultivars
This group of Irises includes those that are cultivars and hybrids of existing species.

'Abiqua Falls'

'Angel Wings'

'Autumn Rose'

'Banana Wind'

'Bernice's Legacy'

'Berry Fulfilling'

'Black Joker'

'Black Suited'

'Bounce'

'But Darling'

'Champagne and Strawberries'

'Chengdu'

'China Blue'

'Code Red'

'Concertina'

'Contrast In Styles'

'Creole Can-Can'

'Coup de Soleil'

'Cubs Win It'

'Cybergrape'

'Double Chocolate'

'Dracula's Kiss'

'Easter Candy'

'Enraptured'

'Entitled'

'Feel the Thunder'

'Fx Schreiner'

'George Barr'

'Ghost Train'

'Giganticaerulea Alba'

'Great Balls of Fire'

'Harvest of Memories'

'Her Highness'

'Here I Am'

'Immortality'

'In Living Color'

'Jurassic Park'

'Lafitte'

'Laughing Lion'

'Longfellow's Gabriel'

'Lovely Senorita'

'Martyn Rix'

'Miss Apple'

'Montmartre'

'Network'

'Nova'

'Off Topic'

'Oregon Firestorm'

'Peach State'

'Pickathon'

'Pink Attraction'

'Pride of Ireland'

'Pure Excitement'

'Rasputin'

'Real Harmony'

'Recurring Delight'

'Restless Spirit'

'Rock Star'

'Roy Davidson'

'Ruth Holleyman'

'Senor Jinx'

'Sharp Dressed Man'

'So Excited'

'Superstition'

'Society Page'

'Stairway to Heaven'

'Swingtown'

'Thornbird'

'Tin Cup Chalice'

'Turkish Dancer'

'Turkish Delight'

'Valentino'

'Vested Interest'

'Wattii'

'Zwanenburg Beauty'

Iris japonica (Fringed Iris, Shaga, Butterfly Flower)
Native to China and Japan, this species produces white to lavender colored flowers that have yellow-orange beards and dark purple markings. It forms a basal tuft of green to yellow-green lance-shaped foliage.

'Aphrodite'

'August Emperor'

'Beni Tsubaki'

'Bourne Graceful'

'Capri Form'

'Caprician Butterfly'

'Crystal Halo'

'Eco Easter'

'Evening Episode'

'Fairyland'

'Frilled Enchantment'

'Kamayama'

'Ledger'

'Nada'

'Pallescens'

'Skirt Chaser'

'Snowy Hills'

'Summer Storm'

'Tenchong Lace'

'Variegata'

'Purple Heart'

Iris kemaonensis (Iris kumaonensis) (Kumaon Iris)
Native to Tibet, Bhutan, India, Kashmir, and Nepal, this species produces yellow-green foliage that remains after flowers have faded. Blooms are fragrant and range in color from lilac to violet. They typically have darker colors and mottling. Plants reach up to 18 inches tall at maturity when in bloom.

Iris laevigata (Japanese Iris, Rabbit-Ear Iris, Shallow-Flowered Iris, Kakitsubata)
This species of Iris is native to Japan, where it is found growing in shallow waters. It is great for water gardens in temperate zones, and produces violet flowers with white beards. Cultivar 'Variegata' has leaves lined with white.

Iris lortetii (Lortet's Iris, Samarian Iris)
With straight, grey-green foliage, this species produces showy flowers in late spring to the middle of summertime. Blooms appear in white and pink or maroon, with purple-reddish beards. Individual plants reach up to

Iris lutescens (Crimean Iris)
These plants reach up to a foot tall and produce broad grey-green leaves. They bloom from March through April in their native range (Northeastern Spain, Southern France, and Italy), where they typically are found in rocky or sandy hillsides or woodland areas. Hardy down to -4 degrees Fahrenheit. Blooms are yellow.

Iris mariae (Mary's Iris, Negev Iris)
These flowering plants are native to desert regions of Israel and Egypt, and produce fairly tall blue-green foliage and lilac-purple to pink flowers with deeper veining and blackish signals and dark purple beards. The species can survive for long periods of time without water,

Iris mesopotamica (Mesopotamian Iris)
Native to the Middle East, this species produces green to grey-green leaves and reach up to 28 inches tall. Each tall flowering stem holds up to 9 blooms. Flowers are violet, purple, lavender or blue, typically with a yellow, white, or orange/white beard.

Iris orjenii (Orjen Iris)
This rare Iris species is native to Montenegro and Bosnia/Herzegovina in the Orjen mountain range. Plants produce white flowers with yellow beards and purple markings, and reach up to 20 inches tall. Flowers bloom in April to June in their native range.

Iris pallida (Sweet Iris, Dalmatian Iris)
These plants are native to the Dalmatian Coast in Croatia, and are widely naturalized elsewhere. It is highly adaptable to different climates. Individual plants reach up to between 20 and 31 inches tall, and produce blue-green leaves. Flowers bloom in May and June, and are pale purple to white with yellow beards. Cultivar 'Variegata' is very popular and produces yellow and blue-green variegated foliage. 'Argentea Variegata' (pictured) produces white and blue-green variegated leaves.

Iris paradoxa
This species, native to western Asia, produces large blooms that range in color from white to mauve to deep purple-black, and have black or purple beards. These plants reach up to 10 inches tall and bloom in spring and early summertime (typically between the months of April and June).

Iris petrana (Petra Iris)
This species is native to sandy desert regions in Jordan and Israel, and produces sword-like grey-green foliage. They can reach up to 10 inches tall and form small colonies over time. Flowers produced by these plants range in color from dark brown to violet. They can be nearly black in certain light.

Iris pseudacorus (Yellow Flag, Yellow Iris, Water Flag)
Native to Europe, western Asia, and northwestern Africa, this species of Iris that produces grey-green foliage and yellow flowers. Individual plants reach up to between 40 and 60 inches tall.

Iris pumila (Pygmy Iris, Dwarf Iris)
This species is thought to be a naturally occurring hybrid between Iris pseudopumila and Iris attica. It is native to a range in central and northeastern Europe. Flowers range in color from yellow to violet, and typically have dark spots on the falls.

Iris purdyi (Purdy's Iris, Redwood Iris)
This species is named for botanist and nurseryman Carl Purdy, and produces cream to peach-colored blooms with maroon to brown veining. Centers are typically yellow, and blooms are present from April through June.

Iris reichenbachii (Rock Iris)
Native to Bulgaria, Montenegro, Serbia, North Macedonia, and Greece, this species produces light lemon-yellow, dull purple or violet flowers in summertime. Stems produce up to two flowers each. Leaves are green.

Iris rossii (Long-Tail Iris)
This species produces narrow, grass-like green leaves and short stems topped with purple flowers. It has creeping rhizomes, which form above-ground rounded tufts of foliage and blooms. Flowers are small and violet (rarely white), and bloom between April and May.

Iris ruthenica (Ever Blooming Iris, Russian Iris, Pilgrim Iris, Hungarian Iris)
This species has a wide native range, from eastern Europe to central Asia. It produces grassy green foliage, and slowly forms clumps via underground rhizome roots. Individual plants

Iris sambucina (Elder Scented Iris)
This species is native to southern and central Europe, and produces green sword-like foliage. Flowers are brown-violet to pink-blue violet, large, and fragrant, smelling of Elderflowers (hence the species and common name).

Iris setina (Iris of Sezze)
This species is native to a small region in Italy, and produces sword-like grey to blue-green foliage. Violet flowers bloom atop slender branching stems. Individual plants reach up to 20 inches tall. Blooms are present from February through March in the plants' native range.

Iris stolonifera
These plants are native to Turkestan, Tajikistan, Uzbekistan, and Afghanistan. They produce grey-green foliage and bi-colored flowers in shades of white, blue, purple, and brown. Beards are blue to yellow and are present on all petals.

Iris susiana (Mourning Iris)
These flowering plants are native to the Middle East, and are considered extinct in the wild due to overharvesting and habitat loss. Flowers are typically white to lavender to dark violet purple, with very intricate darker lines and markings.

Iris tectorum (Roof Iris, Japanese Roof Iris, Wall Iris)
These flowers are native to China, Korea, and Burma and produces clumps of green, strappy foliage. Blooms are lavender to purple-violet, and have white and yellow-orange markings towards their centers. They flower between the months of April and June in their native range.

Iris tenax (Tough-Leaved Iris, Oregon Iris, Flag)
Native to Oregon and northern California, this species is found along roadsides, in grasslands, and in openings in forests. IT produces flowers that are lavender-blue to purple, with white, yellow, and darker markings. Leaves are very slender and green, almost grasslike. Rhizomes spread slowly.

Iris variegata (Hungarian Iris)
This species has dark green, ribbed foliage, and produces tall branching stems topped with yellow-white flowers that have purple to brown veining. This is a hardy species and does well in temperate regions.

Iris verna (Dwarf Violet Iris)
Endemic to the eastern United States, this species grows in semi-shaded woodlands, and prefers nutrient poor acidic soils.

Iris versicolor (Iris versicolour) (Blue Flag, Harlequin Blueflag, Larger Blue Flag, Northern Blue Flag, Poison Flag, Purple Iris)
These purple flowers are native to North America, where they grow in meadows, marshes, shorelines, and streambanks. It reaches up to 31 inches tall when mature and in bloom. Flowers appear from May through July.

Caring for Iris

Iris flowers can be purchased as seeds, nursery starts, or as bare roots. Nursery starts can be planted in springtime, and will generally flower in their first year in the ground. Bare roots can be planted in the fall or spring, and may not produce full flowers until their second year in the garden. The rhizomes should be planted horizontally, with the top exposed and only the roots under the soil surface. In areas with very hot summer temperatures, plant rhizomes just below the soil surface. Irises grown from seed will mature and flower within three years. To direct-sow Iris seeds in the garden, place seeds about 1/4 inch deep. Iris plants should be spaced between 12 and 24 inches apart for best coverage and airflow. Some of the taller Irises can benefit from being grown against a wall or fence, or be staked. They should be planted in a place in the garden that receives between 6 and 8 hours of sun each day. In warmer climates, Irises appreciate some afternoon shade when temperatures are at their peak. Ensure that soil is well-draining, fertile, and has a pH of between 6.5 and 7.5. If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing.

Water new plantings regularly as they establish a strong root system. Mature Iris plants like moisture, as well, but most do need well-draining soil to avoid root rot issues. As a general rule of thumb for most Iris varieties (excluding Water Irises), water when the top two inches of soil feels dry to the touch. Do not mulch around the base of Iris plants; mulching Irises can encourage their rhizomes to develop root rot issues. Each year in springtime, apply a 2-inch layer of organic compost around the planting area to improve soil structure, drainage, and nutrient load. This feeding should be sufficient to provide these flowers with enough nutrients to get through their growth and flowering seasons. Fertilizing these plants is rarely necessary; they do not like high-nitrogen fertilizers. Prune Iris flowers after blooms fade by cutting flowering stems back to their base (unless you will be collecting seed for propagation). Deadheading Iris plants can encourage more blooms to form. Every three to five years, clumps of Iris should be dug up and divided. During division, any parts of the roots that have been affected by Iris Borers or disease can be culled. Dividing Irises keeps plants at their most resilient, and also allows for propagation. For instructions on how to divide Irises, see the Propagation section below.

Growing Iris In Containers
Although it is uncommon, it is possible to cultivate Iris plants in pots. Dwarf species and cultivars are best for this situation. Ensure that the pot being used is at least a foot wide. Potting soil should be loose and free-draining. If soil does not drain well, amend with sand or perlite. It is also important to make sure that the pots have adequate drainage holes before planting. Leave the tops of rhizomes exposed or just barely covered. Water new plantings regularly as they establish a strong root system. Mature plants should get watered whenever the top inch of soil is dry to the touch. Take care to not overwater. In cooler climates, move containers into a sheltered location over the winter months. When grown in containers, Irises will need dividing every other year. For instructions on how to divide Irises, see the Propagation section below.

Propagation

Irises can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Iris plant, follow the instructions below:

Propagating Iris by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
In either late winter or early springtime, get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes between 4 and 12 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Iris by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.

Iris seed pods form after flowers have faded.

Iris seeds are typically small and light brown to tan in color.

Problems and Pests

Iris flowers can suffer from the following pests and diseases in the landscape:

Iris Borer Worms
Bacterial Soft Rot
Crown Root Fungus
Fungal Leaf Spot
Mosaic Virus

For more information on these pests and diseases, including how to treat and manage them, consult the links below:

Pests & Pest Management

Plant Issues

Gallery

Bees are important pollinators of Iris flowers.

This mixed bed features various Iris and Foxglove cultivars.

Water Irises prefer boggy areas, and like to have their crowns under water year-round.

Here, a central round bed features yellow Irises around a vine,

Light purple Iris flowers compliment ornamental Allium.

Irises are classic garden ornamentals.

Hummingbirds will visit Iris flowers in the landscape.

A diagram of the various parts of an Iris flower.

Irises, especially dwarf ones, do well in containers.

Videos

How to dig and divided Irises successfully.

Check out this dwarf Iris bloom timelapse video.

How to plant Irises in the garden.

Take a look at different varieties of Bearded Iris in this garden tour.

How to care for Irises - the complete guide.

Learn how to grow Irises.

Resources

Bearded Iris: Care and Growing Guide

How to Grow Iris

How to Grow Irises: The Complete Iris Flower Guide

Wikipedia: List of Iris Species

Wikipedia: Iris (plant)

The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 377 - 381, Iris

If you have any questions, comments, concerns, or photos you’d like to add to the gallery, please let me know by sending me a message using the button below!

Send A Message

Previous: Ipomopsis

Plant Identification II

Next: Ixia