Iris Basics: Planting and Caring for Your Irises

Iris Basics: Planting and Caring for Your Irises

Bearded irises are quite easy to care for.  They’re native to semi-arid regions and are very drought-tolerant.  Here we’ll show you how to plant them and give them what minimal care they need.

Step One: Labeling Your Irises
This is a step that is often overlooked.  Labeling your irises is critical if you wish to keep track of them.  There are many commercial labels available, and many gardeners make their own by cutting strips from slats of old window blinds, .plastic containers, or milk cartons. Whatever you use, do not mark the names using a Sharpie, because the ink fades. (The jury is still out on the new Sharpie Extreme, which is supposedly fade-resistant.)  The best thing to use is a soft #2 pencil, as graphite will remain on the tag for many years.  If you rough up your tag with sandpaper, a pencil will write on plastic very well. As an insurance policy, always bury an extra tag under the rhizome when you plant it.  Chipmunks, crows, even curious deer will pull up or move tags occasionally, and if your tag disappears, you’ll be able to recover the name when it’s time to divide the clump.  If you want to paint the name on rocks, try using an automotive paint marker, as the paint is UV-stable.

Step Two: Planting Your Iris
First, mound up a bit of soil where you want the iris.  The top of the mound should be about level or a little higher than the surrounding garden area, to promote good drainage.

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Then lay the iris on the mound, spreading out the roots.

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Finally, cover the roots with soil and tamp down.  Do not cover the top of the rhizome with more than 1/2 inch of soil.  It will eventually work its way to the top of the soil and the top of the rhizome will be exposed.  This is normal.  If you are planting in a climate that gets cold winters, lightly covering the rhizome for the first winter will give it a bit of protection.  (Photos courtesy AIS Encyclopedia)

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Step Three:  Watering
After planting, water well to help the rhizomes develop their root systems, and continue watering until the first good rain. If lack of rain persists, watering should be deep enough to penetrate the shallow root system. Less-frequent, deep watering is better than frequent, shallow watering. Once established, irises should be watered when the top three inches of soil dry out.  Remember, irises are native to semi-arid climates, and over-watering them is a common mistake.  When in doubt, err on the dry side.

Step Four:  Fertilizing
Irises don’t like high-nitrogen fertilizers, because they encourage soft growth that is prone to rot.  Use a balanced 10-10-10 or low-nitrogen 5-10-10 fertilizer, or a superphosphate.  Apply lightly in the early spring and again about a month after blooming is done.  Sprinkle it around the rhizome, not on top of it.  Alfalfa pellets or alfalfa meal are  great additives to mix into the soil when planting.  Bone meal is another good additive when planting, as it’s rich in phosphates.

A note on blooming:  Don’t be discouraged if your iris blooms are sparse the first spring after planting.  It will sometimes take an iris a year or two to get established.  You should see noticeably more blooms the second spring, and even more in the third year.

Eventually, your irises will need to be divided.  Let’s move on to Dividing and Sharing.

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