 Sunday, August 19
The bold and the beautiful
Now’s the time to plant irises, a hardy, drought-resistant plant
If garden centers were organized by fashion categories, bearded irises would be in the vintage section.
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The Daily Journal/Kim Carpenter
Black German irises steal the show in Lynn Madison’s Joliet garden. |
With their full, ruffled falls, lush upright petals and dizzying array of color combinations, they are the Victorian ladies of the garden. But an “old-fashioned” reputation certainly needn’t limit them. At over two feet tall, a vase full of these architectural beauties can also make a bold, modern statement.
Because bearded irises are extremely drought tolerant, they are great plants for our area. They do not need to be watered, unless we’re in the midst of a severe drought. If your garden stays wetter, try Siberian, Japanese and yellow flag iris instead of the bearded variety. They are much more tolerant of moisture and can even be grown beside ponds. If you have clay soil — a.k.a. bad drainage — you will need to amend it with organic material. Bearded irises do not like to be wet. (It will contribute to bacterial soft rot.)
What a mess
Bacterial soft rot: Ah, yes... Just saying that phrase brings back poignant memories. I spent four summers at a perennial farm scooting from one iris plant to the next, scooping out the yellowish mush with an old kitchen spoon and plopping it into an empty coffee can.
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| An American Iris Society award winner, “City Lights” is one of the newer reblooming bearded irises. |
Bacterial soft rot is easy to discover. Tapping or pressing on the top of an infected rhizome will reveal a softness, mushiness, or even ooze. And, once you’ve smelled soft rot, you’ll not be likely to mistake it for “age.” That smell is indicative of a pressing problem. You’ll need to discard the infected plants (do not compost them). If the rot is rampant and you’d like to try to salvage some plants, scoop out the rot until only clean rhizome is visible, then rinse it in a 10-percent bleach solution. Be sure to clean your spoon and any other tools in the solution, as well; soft rot will happily spread if given the chance. Replant the clean rhizomes in a different location.
While rot is the most common affliction among bearded iris, it is not the only one. Iris borer is a small worm that usually precludes rot. The borers overwinter in decaying iris leaves and then crawl up and begin to chew their way down through the fresh leaves until they get to the rhizome, which they proceed to mine through as well. In the wounds they leave behind, rot develops.
Crown rot fungus, leaf spots, and mosaic virus are additional enemies of iris. The best method of control is simple prevention. Every fall, cut the foliage down to six inches and discard the dead leaves. Sun, ventilation and drainage are essential for bearded iris.
Because irises bloom in the spring, a July/August planting is best. After August, the plants may not have sufficient time to build up reserves for the winter. A spring planting will probably negate an entire season of bloom. Be sure to plant shallowly; the top of the rhizome should be flush with the soil, and therefore, visible. If you choose to fertilize, be sure to use a low nitrogen selection, such as 5-10-10. Bone meal or superphosphate is also a good choice. Planting too deeply, or applying a high nitrogen fertilizer, will increase your likelihood of rot. Remember, rot is stinky. You want to avoid it.
Consider extending your irises’ season of bloom with careful planning. Bearded iris come in four categories: The mini dwarf (4 to 9 inches high) bloom in April; standard dwarf (10 to 15 inches) bloom in early May; intermediate (15 to 28 inches) flower in mid-May; and tall bearded (28 inches) finish the show in late May. With hybridizing, more and more bearded irises are capable of reblooming in late summer/early fall.
For a list 20 recommended reblooming varieties of bearded iris — and other local gardening information — visit www.oramentals-edibles.com
Divide and conquer
If you plant an iris, mark my words, at some point you will divide it. Bearded irises grow themselves into oblivion. Rather than intelligently spreading to the farthest ends of the earth, they grow into a circle, like one very close-knit family. After five years, they’re landlocked by their iris relatives and begin to dwindle.
Dividing them is not difficult. Several weeks after flowering has ended, use a fork or spade to lift the plant from the soil. Iris are shallowly planted and rooted, so lifting it out is considerably easier than lifting, say, a daylily. After removing excess soil, you can begin to break or cut the rhizomes apart. Old rhizomes, which are visibly shriveled, should be composted; their flowering days are over.
Each divided plant should have one fan of foliage and one firm, healthy rhizome with several white roots. Cut the foliage back to six inches in length and rinse off any excess dirt. If you have a number of different varieties, I would recommend marking the name or description on the leaves with a permanent marker to avoid confusion when replanting.
Once you’ve gotten them all cleaned, trimmed and marked, lay them out in the sun to dry. Irises are droughty sun-lovers and this bare-root sunbath proves it. Once they’re dry, you can replant them, ship them off to your gardening penpal, or store them in a cool dry space for several months. |
 Mollie Uftring developed a green thumb as a teenager working in the perennial beds at Hornbaker Gardens in Princeton, Illinois. After graduating from the University of Illinois with a degree in ornamental horticulture, she worked as a landscape designer in Ohio before returning to Illinois.
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