Bearded Iris 101
Iris season is almost over, and I’ve delighted in catching glimpses of these lovely party girls of the spring garden as I drive about on errands.
I recently rediscovered this haiku that I wrote years ago. It was inspired by the dismaying sight of my beloved heirloom irises facedown in the mud after the downpour that inevitably seems to arrive every May just as they are in their full glory.
Sweet iris unfurls
butter and velvet petals
Sad wet party dress.
Iris, or flags as my mother always called them, are one of the first flowers I learned to identify as a child. An old purple form grew in a bed that stretched the length of the driveway at my childhood home. They were an impressive sight, with their royally inked purple velvet petals veined in mauve.
The Story of Bearded Iris
Bearded iris, or Iris x germanica, is one of the world’s oldest cultivated flowers, and the oldest garden iris. They were carved on Egyptian temple walls, mentioned in Gerard’s Herbal in 1597, and by the 1920s ranked as one of the top three perennials in North American gardens. Almost everyone who loves gardens has a soft spot for these beauties.
Irises are named for the Greek goddess of the rainbow, which seems fitting, as they do come in almost all colours in the spectrum except green and true blue. 9th century Benedictine monk Walafrid Strabo mentions bearded irises growing in his monastery garden. The white version, ‘Florentina’ was introduced by 1596, and is the plant that orris root, commonly used in perfumes, is sourced from.
The tall bearded irises that we love in our gardens today began to be hybridized around 1800 in Germany and France. By 1840 hybridizing fever was in full swing, and tall bearded iris hybrids numbered 100. The number of cultivars thought to be available to gardeners now numbers around 60,000! How is a gardener to choose?
Bearded irises are so resilient and tough that they can still be found thriving in long-abandoned homesteads and cemeteries today.
Anatomy of a Bearded Iris
There are three main parts to a bearded iris flower: the standard, the falls and the beard.
How to Grow Bearded Iris
Bearded irises are easy to grow, although they will not thrive in wet, heavy soil. They crave warm, dryish conditions, loving my hot, sunny Okanagan garden to the point where I have to divide them every couple of years.
Bearded iris grow from rhizomes, meaning they have fat tubers rather than typical root systems. Choose a spot in full sun with well-drained soil. Dig a shallow hole then mound the soil up in the middle. Lay the rhizome on the top of the mound and spread any roots down the mound. Fill in the hole with soil, ensuring the top of the rhizome lies just above the soil. They will survive a bit of drought.
Every 3-4 years you will notice the rhizomes at the soil surface looking very crowded, and this is when they need dividing. If you omit this task flowers will be fewer and fewer each year. Divide in early spring or in summer well after bloom is finished. Dig up the rhizomes carefully and lay them out on a tarp or the ground. Gently dust off the soil and use scissors or pruners to trim off the foliage down to one-third. Use a small sharp knife to cut the rhizomes into two smaller ones, and lay these back in the bed (you can amend the soil a bit before doing this) with the foliage ends pointing out, spacing each rhizome around 8-12″ apart. Cover with soil, again leaving the tops of the rhizomes exposed, and water in well.
Dividing is an amazing way to (a) increase your iris population if you have room for more, and (b) share them with friends and neighbours. To share, place the rhizomes in a bag and mark it clearly with the variety name and colour. I’ve even left bags of iris rhizomes out on the boulevard, where they are usually snapped up by people walking in the neighbourhood.
How to Find Heirloom Bearded Iris
Fortunately there are still many heirloom bearded irises available, maybe because they are so hardy. Here are a few places to learn more about and source old bearded irises:
- Old House Gardens in Ann Arbor, Michigan. Their iris listings are a rich and valuable resource of information for anyone who wants to add some historic bulbs or rhizomes to their garden. If you don’t live in the United States, familiarize yourself with the old varieties in their listings then put your detective hat on and search for someone in your country who might be offering them.
- Iris Societies. In Canada try the Canadian Iris Society. Their website has loads of educational info on identifying and growing the various types of iris. In the US try Historic Iris Preservation Society. I follow both of these societies on Facebook, where members post lovely photos of heritage irises regularly. It’s a great way to identify one you might have, or fall in love with an heirloom iris and go down the rabbit hole trying to find it. That’s part of the fun!
- Look for nurseries in your area specializing in irises. Here in the Okanagan, Hillside Irises in Cawston grows and sells many kinds of irises. They are not identified with their date of introduction on their website, but if you see one you like, you can search it online and hopefully get lucky.
I recently ID’d my own bearded iris as ‘Loreley’ with the help of Old House Gardens. ‘Loreley’ was introduced by a German breeder in 1909 and was one of the most popular bearded iris in the 20th century. Find out more about Loreley and how she came to be in my garden.