Thursday, October 09, 2014


 Dana Prom Smith


          In early spring when the stunning white of the snowdrifts gives way to patches of mud and dirty snow, bright, cheery daffodils are amongst the first to bring the promised beauty of spring.  The bearded irises are next.  One of the most complex and beautiful flowers ever to grace a garden, the word “iris” is a Greek word meaning “rainbow,” “halo,” or “messenger of the gods.”  The plural in Greek is irides from which we get the word iridescent.  John of the Apocalypse writes:  “Then I saw another mighty angel coming down from heaven, wrapped in a cloud, with a rainbow over his head, and his face was like the sun, and his legs like pillars of fire (10:1).” 


Irises are both tough and beautiful.  Tough means they’re hardy, but it doesn’t mean they can be neglected.  They need care, such as nutrients and bedding, and if cared-for well, they will return the care with a nonpareil beauty.  Care begins with bedding.  The makings of good bedding are aplenty in the high country, clay, cinders, and compost.


          If a gardener is clay, add cinders, and if cinders, add clay.  Irises like a soft, friable bed.  They also like lots of compost.  The best bed has good drainage because they don’t like it soggy.  But who does?  Irises will tend to rot if swamped out.


          With irises it’s important to start out well because unlike annuals the beds can’t be enriched with compost each year.  Those rhizomes are going to be stuck in that bed for several years.  One of the big items in caring for irises is giving them a low nitrogen and high phosphate fertilizer (6-10-10) six weeks before they bloom and right after they bloom and super-phosphate or bone meal (0-10-10) in the fall.  Since irises are all root, they need phosphorus to promote root development.  With too much nitrogen, as in lawn fertilizer, they will tend to rot.


          Irises do best in a sunny location with at least six hours of sunlight a day.  As far as water is concerned, they’re a xeriscaper’s dream.  In the high country, they need water when they’re planted until the new center leaves appear.  During dry spells, they’re best watered every 3 to 4 weeks, and again in the spring before blooming.  Also, they’re best mulched before the snows of winter with the mulch removed after the last hard frost.


          The best time to plant iris rhizomes in the high country is in the early fall, giving them enough time to get their roots established before the winter freeze comes.  After the soil has been enriched, make a shallow hole in the soil about twice the size of the rhizome with a small mound of soil in the center.  Put the rhizome on top while draping the roots down the sides of the mound.  In Flagstaff because of our cold winters, the soil should slightly cover the rhizome.  Do not plant them deep.


          Irises can be attractively planted in groups of three throughout a yard, 12” apart, with the toes pointing inward in a triangle.  If planted in rows, all the toes should point in the same direction to avoid crowding, spaced 18” apart.  Remember to keep the soil in which the rhizomes are planted moist for two or three weeks until the first news leaves appear.


          After blooming, the stalks on which the flowers appear are best removed, not to drain energy from the plant.  Every three to four years, irises should be replanted to prevent overcrowding and to encourage renewing.  This is generally best done a month or so after blooming.  Clumps can be renewed by removing the old center of the clump or by digging up the entire clump and removing the old plant and replanting the newer rhizomes with the fans attached.


          Irises come in many sizes for many tastes.  The tall bearded irises when planted in a circle or triangle appear as though they were a lush aureole of exotic colors hovering above the garden betraying their name “rainbow” or “halo.”  When studied, one can even hear the messengers of the gods.

Copyright © Dana Prom Smith 2014

Dana Prom Smith and Freddi Steele edit Gardening Etcetera for the Arizona Daily Sun.  Smith emails and blogs at






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