Thursday, July 8, 2010


Iris grow from RHIZOMES, not bulbs, and so we don't wait until fall to plant them.  Unlike other perennials, they can be planted, transplanted and divided any time now, through August.  I start dividing and planting now.  This gives the rhizomes a great start, and ensures that their roots will have plenty of time to be well established by the time colder climates arrive and the growing season is over.  I think it's easier to transplant or divide them now, because the root systems of the new fans are less mature, making them easier to pull or divide.  Pick a place where it's sunny--they need at least 6 hours of sunlight a day.  And it's very important that the place you choose has good drainage--standing water is fatal to iris.  If you need to, raise the bed a little, and plant on a mound, to keep the water drained away from the rhizomes.  Another important thing to remember is to not plant them too deeply; they like the tops of their rhizomes  exposed to the sun.  I plant mine with a small handful of triple super phosphate. Spread their roots out, and water them in.  Make sure they get enough moisture when establishing root, but make sure you don't water too much, they will rot if you do.  Plant them anywhere from 1 foot to 2 feet apart--the closer you plant them, the sooner they will need to be divided.  I plant mine closer, because I'm willing to divide sooner, and also because I don't have the room for large clumps of individual iris--I have 161, and have them interspersed with other perennials in the beds where I can't have large clumps.  So, I plant mine 12 inches apart, and divide every 2-3 years, depending on the cultivar and its' growth.  If iris are allowed to become overcrowded, the blooms will suffer, as well as the vigor of the plant.  Once they are established, iris don't really need to be watered except for times of  drought-like conditions.  Iris like a neutral pH.  Here in Utah they do very well, and no fertilization is really needed.  But, if you do want to fertilize, a light side-dressing of 5-10-10, 6-10-10, bonemeal, or, my favorite, super triple phosphate, can be used in early spring, about a month before they bloom, and they can benefit from a fall dressing of bonemeal.   After they are established, they really need minimal care.  In fall, just cut their leaves into a fan, to about 6-8", unless their leaves are diseased or damaged, and if they are, cut off immediately.   Never use anything high in nitrogen, as it will rot the rhizomes.  Now is a good time to order or trade iris.  It's also a good time to revamp your iris beds if needed.   If you're not dividing or thinning, remember to break off the old bloom stems right to the ground; that stem will never grow and bloom again.  If you plant new rhizomes, and live in a colder climate region it is recommended that you give them some winter protection--just make sure you remove it in early  spring. 
Susanne Holland Spicker Mother, Grandmother, Homemaker, Gardener, Teacher, Photographer

Passion is defined as the love of, or the object(s) of affection and emotion. I am passionate about family, friends, flowers, food, photography and fabulous music! This blog is dedicated to those loves.

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