Iris: A historic long-lasting flower for ever garden
Irises are a marvelous garden flower that have made their way from the wild woodlands into the world's most prestigious gardens. Along the way, they became a renowned commercial crop, since the fragrant roots were an important ingredient in many perfume formulations.
Today, gardeners have access to an ever-expanding selection of irises, ranging from diminutive and historic to flamboyant space-age varieties. Here's why there's a growing iris obsession taking root in my garden.
I hope that this page inspires you to take a chance on growing these elegant, long lasting flowers.
Are You Growing Irises?
Queen of May - This Bearded Iris That Started it All
Many years ago, this was the only iris growing around my quaint hand-built rental house. Given the nature of this historic farmhouse, it figured that any plants found here would be older varieties. After studying many a photo, one kind gardener suggested that I might be "Queen of May," a historic cultivar that was hybridized by a fellow called John Salter, who was active before 1859. This charming variety has soft lavender blossoms with distinctive veining, and like most irises, it's easy to care for and spreads across the garden naturally.
Caesar's Brother - A Classic Siberian Iris
Then came Caesar's Brother. I spied this royal purple beauty at the local garden center at the end of my road, and knew I had to have it! Unlike the tall bearded irises that are traditional, this is a Siberian variety from the speciesIris sibirica
Other famous iris species are the Japanese and Louisiana irises, which both tolerate wet, boggy, pond-like conditions.
Siberian irises have strong, woody rhizomes and tenacious roots that allow them with withstand moisture and drought. The foliage is elegant, long and slender and stands nearly 4 feet tall.
This beautiful cultivar was registered in 1932 by the well known Canadian hybridizer Cleveland Morgan, who co-founded the American Iris Society. Caesar's Brother went on to win the eponymous Morgan Award in 1953.
Iris Anatomy - What is a Rhizome?
At first, a rhizome might seem suspiciously similar to a bulb, but it's actually quite different. Bulbs have roots, scales or onion-like layers where a shoot of leaves emerge from. However, rhizomes are a solid, woody modified stem that grows horizontally just under the surface of the ground. Like bulbs, rhizomes also have roots and a bulbous portion where the leaves emerge from.
With irises, the rhizome continues to generate new babies (offsets). The parent rhizome flowers once and secondary rhizomes are produced and will flower in subsequent years. That's why it's necessary to divide rhizomes and remove the unproductive parents that can clog your flower beds over time.
As you can see in the picture, the rhizome has three parts, the parent in the center, which holds the flower stalk, and two baby rhizomes that currently have one fan each and will develop flowers next spring.
How to Plant Iris Rhizomes - Tips and Techniques
This best time to plant or divide irises is after they flower, specifically six weeks after flowering--as long as temperatures are under 90 degrees. This can be done through the fall, if there are several weeks for the irises to get established before the first frost is expected.
Here's how you can plant your irises for best results.
1. Start with a well-prepared, weed free flower bed.
2. Dig a series of shallow holes at least 10 inches apart. Arrange the holes in a pyramid-shape (like bowling pins) to create a formal display. Generally, you'll want to have an odd number of plants, following the landscaping rule of threes and fives to create the most pleasing visual effect.
3. Water each hole thoroughly.
4. Once the water has drained, place an iris in each hole. For an organized look, arrange so each fan is facing the same direction.
5. Back-fill the soil around the rhizome, making sure that the top of the rhizome is visible above the soil line.
6. Water thoroughly.
7. If the leaves haven't been cut, trim now for stability.
8. Water weekly until established if there's no rain or if temperatures are hot.
9. Irises are "established" when a new leaf emerges in the center of the fan.
Irises don't require much care or fertilizer. If desired, fertilize once per year with a balanced, low-nitrogen fertilizer, such as 5-10-10. Worm castings are also beneficial.
Never mulch irises.
Resist the urge to over-water.
Also, avoid piling additional soil over the rhizome.
Divide mature rhizomes every three or so years.
Remove spikes after flowering.
Cut back foliage if desired after bloom.
Label plants with permanent tags.
Expand or Start an Iris Collection
Choice varieties are plentiful, fairly affordable and easy to find on eBay.
Five Reasons to Love Irises
1. Rhizomes last for decades and clumps spread naturally.
2. Unlike bulbs, rodents, squirrels and other hungry critters won't eat your rhizomes!
3. Irises are hardy, disease-resistant and easy to care for.
4. There are hundreds of modern and historic cultivars in nearly every color and shape imaginable.
5. Irises can be grown almost anywhere from frigid Zone 3 all the way to the tropics of Zones 8 and 9.
Record Keeping for Gardeners
Keeping track of what you're growing is essential garden work. It's even more important if you want to breed your existing plants and take your hobby to the next level. Because irises look so similar when they are out of bloom, labeling and recording keeping is critical.
To keep track of all the new varieties I added, I did a few things.
1. First, I created a simple list of all 21 irises in my garden, including plant names (if available), the name of the hybridizer, date of introduction and a brief description of the bloom.
2. Then, I sketched the garden to make sure that the location of each numbered plant was clearly marked, so I wouldn't lose track while I was finishing the labeling process.
3. Finally, I made write-on plant tags from a bunch of aluminum cans. These will be a permanent marker of what's growing there. (Check out my tutorial if you'd like to make your own metal plant tags.)
4. Once the markers were in place, I made a better landscape architect-style diagram of all the irises and other plants in the garden, including each number as a reference for all of the varieties.
Once of my goals is to cross pollinate some of these gorgeous flowers and try to create my own unique hybrids. After germination, it takes 2-3 years for blooms to develop on the seedlings.
Since irises are so diverse, hybridization has fascinated many people over the past several centuries, including doctors, hobbyists and leading geneticists.
Since a plan to bread some of the classics irises, I'll share everything that I have discovered.
First, to create unique seeds, you need a pollen parent and a pod parent, that will bear the seeds. To prevent self-fertilization, the anthers of the pod parent must be removed. Then, pollen taken from another plant can be applied to the carefully covered receptacles. Then, you wait for the pod to form and dry, so that the seeds can be harvested and planted.
Irises have many different characteristics. For example, height, flower size, color, bloom time, the ability to rebloom and much more. Breeding can bring out any of these tendencies. However, certain colors are dominant while others are recessive.
Understanding the Pigments that Give Irises There Distinctive Colors
Water soluble anthrocynanins, the pigment found in the skin of red apples, are dominant. Nearly 2/3s of irises display these colors.
Anthrocynanins are found in different concentrations in irises that are purple, blue, red and violet.
Carotenes, the oil-soluble pigment that gives carrots their orange tone, is responsible for coloring the 25 percent of so of irises that are yellow, golden-yellow, orange and rusty red.
White irises are produced when these pigments are genetically blocked, basically they are albinos.
Recessive and Dominant Traits in Irises
Other traits are also dominant and recessive.
Veining, for example, is dominant.
Plicata, the soft feathery shading around the petals, is recessive.
A combination of dominant and recessive colors may also produce an infusion, or color overlay, where it's nearly impossible to tell which hue is dominant.
An Introduction to Hybridizing Irises
Learn about the anatomy and basics of hybridizing irises from Yale geneticist and iris specialist Dr. Kidd. View part 1 and part 2 below.
Irises in my Garden
Since then, I have added a number of other varieties to my garden. Most were purchased from my local iris society's annual sale. This is a great way to expand any collection. I will add pictures to these entries when the bloom.
Iris hybrida 'Orinoco Flow'
Irises Purchased in 2014
1. Orinoco Flow
Hybridized by Bartlett 1989, introduced 1993
White with indigo shading around the edges (plicata)
Hybridized by Maryott 1991
White self with red beards (the little fuzzy bit)
3. Indian Chief
Hybridized by Dr. Wylie Ayers of Ohio 1929
A robust variety and common no-ID iris.Two-tone dark violet with burgundy falls (the lower petals)
4. Spanish Peaks
Hybridized by Dr. P. A. Loomis of Colorado 1947
A notable pure white iris, considered to be one of the best of this color
Cross: Dominion x purissima
5. Feu du Ceil
Hybridized by the French family Cayeux - released in 1993
Bright orange throughout
6. Vert Galant
Hybridized by Ferdinand Cayeux, patriarch of the French family, registered in 1927
Bi-color flower with blushing nude standards and velvety burgundy-tone falls.
This is yet another historic Cayeux iris registered in 1927.
Blushing rose petal pink with yellow beards and yellow veining. Height 4 ft
8. Iris Swerti
A natural hybrid discovered in 1612
White with lavender plicata shading. Petal are pinched and curled inward. Produces a bright, lively clump.
9. Afternoon Delight
Hybridized by Ernst 1983
Golden, Tan and lavenders with a white infusion.
10. Iris pallida (literally pale)
Collected by Lamarck in 1789
One of the original Orris root cultivars, grape-scented flowers.
A classic that many modern and historic varieties are descended from.
A natural hybrid known since the 1500s.
Pale white flowers with a grayish opalescent cast and yellow beards.
Cultivated throughout Italy for its valuable orris root.
Also in the garden, eight unknown varieties that will be classified after flowering.
A few unknowns have already been classified.
a. Joyce Terry (1974) -- yellow with yellow plicata and white on falls. Early to mid-season bloomer. 'Charmaine' X 'Launching Pad'.
b. Immortality (1982) -- large white blooms with subtle olive-tone veining. It has a light fragrance and is said to rebloom. Cross between "I Do" x "English Cottage."
Iris hybrida 'Immortality'
Tips for Identifying Unknown Irises
When my unknown irises bloomed, I was eager to attempt an ID. Joyce Terry was fairly easy to identify. I Googled the color and bloom time. I also went to one of the well-known Iris sellers and searched their catalog by color and bloom time. Some looked similar, but were introduced too recently, so I was confident that I had the correct name. I was also able to identify 'Immortality.'
In the end, I felt satisfied that I had been able to find the registered cultivar and happy that I had two popular cultivars.
Iris hybrida 'Joyce Terry'
2015 Iris Additions
New Irises in My Garden
My "iris virus" continued in 2015. Here are some of the varieties that I welcomed into my garden that year.
Hybridized by Bliss, Majestic is a bi-tone iris with lavender standards , dark velvety purple falls and lemony yellow beards. IT has a small amount of veining around the beards and resembles the classic "germanica" iris to my eye. It's a strong, free-flowering iris. Increases rapidly. This is a cross between Dominion and an unknown parent.
This mid-season TB was hybridized by William Mohr and Sydney Mitchell (collectively known as Mohr-Mitchell) It's single known parent is "Bruno," a grape-scented descendant of "Dominion." The standards are multi-colored with bronze, red and violet hues. The falls are more strongly colored. Flowers are borne close on 45-inch stems.
Hybridized by Kleinsorge. This is a bi-color tall bearded (TB) iris with rusty maroon falls, sandy standards and brilliant gold beards. Falls are delicately veined. Resembles a highly colored Rameses and its colors are similar to Mary Geddes. (((Conquistador x Cardinal) x Carfax) X Rameses). This is a mid- to late-season bloomer.
Helen McGregor (1943)
This distinctive iris is "self" white with strong a lavender/ice blue tint and shaded beards that go from golden yellow to near white. The galls and standards are slightly ruffled. Helen McGregor won the Dykes Medical in 1949. This is a cross between the ever popular Purissima and Cloud Castle.
Cherry Glen (1994)
This is another cultivar developed by William Maryott. It's a mid-season bloomer with heavily ruffled petals that have a rich grape purple color. The falls are slightly darker and more velvety. The beards are bright golden-orange. Best of all, the flowers have a spicy fragrance.
True Believer (1994)
This 1994 introduction features creamy tan standards paired with periwinkle blue/lavender falls with a tan infusion and lighter edges. Beards are golden orange. Mid-season bloomer. This is a cross between 'Edith Wolford' X 'Betty Simon'.
Textronics is a glorious royal purple tall bearded iris. It blooms early and has a sweet scent. The petals are heavily ruffles, the falls are gradient and the beards are white with brilliant orange tips. This is the products of several crosses. Textronics was hybridized by Tom Burseen.
Glowing Smile (2001)
This newer cultivar features white standards, yellow style arms (in the center of the flowers) and falls that are shaded yellow with a white edges. The beards are also yellow. The edges of the standards and falls are ruffled. This was hybridized by Ben Hager and introduced by Cooley's Gardens. The at least four or five crossed with hybridized with the parent "Liz."
Broad Shoulders (2001)
This full-contrast iris displays peachy, apricot or creamy pastel pink standards juxtaposed again rich wine-colored falls that have thick ruffles and a rich velvety texture. The colors are officially described as pallid lavender for the standards, port falls and henna beards. Either way, it's a luxurious introduction from Keith Keppel.
I also added seven unknowns, inducing a pink and one red.
Iris-related Resources to Grow Your Passion
- Iris Encyclopedia
This comprehensive database includes modern and historic iris cultivars. Many have pictures and nearly all have detailed descriptions. This probably won't be helpful if you need to ID an unknown, but it's great if you want info on a named plant.
- List of Iris Hybridizers
Official list of hybridizers and award winners from the American Iris Society.
- Historic Iris Photos
Photos, comparison tools and detailed descriptions of historic irises from the Historic Iris Society.
- Article on Iris Hybrids
A scientific 1923 article on irises and their traits.
- Iris City Gardens, Nashville
Iris City Gardens in the greater Nashville area is a mail order source, specializing in beardless iris including Siberian Iris, Louisiana Iris, Crested Iris and antique bearded Iris.
- Irises at Montecello
A comprehensive list of historic irises cultivating at Thomas Jefferson's Montecello.
Have you had good luck growing theses historic flowers, do you want to give them a try? What kinds are you growing?
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.