by Melody Kendall

Spring is amazing! The plants in the garden, seemingly overnight, leap out of the ground in a mind- boggling array of varying shades of green and early bloomers.  I find that I, too, am rejuvenated and invigorated with the crisp cool mornings and warm breezy afternoons. With the current stay at home directive I really appreciate it.

The most recent show stoppers in my garden are my bearded iris or Iris germanica.  I'm embarrassed to say my iris are much ignored and not nurtured. It has been years since I made a shopping trip to a local Iris farm and did as we all tend to do, bought way too many.  When I got home, I wondered where I would plant them. I decided to read the planting instructions, another concept that often seems foreign.

Bearded Iris are not bulbs like tulips, but are rhizomes. They look similar to a small lobster tail. Rhizomes should be planted in late September or early October in rich, loose soil close to the surface (½ inch) with the small leaf buds at the top. To avoid possible rot, make sure the soil drains well and avoid excess moisture by not applying mulch. The plants do best in full sun but will tolerate part sun. The eventual location of my rhizomes is in a 12” wide bed with southern exposure. They run between a fence and landscape timbers for the entire 40-foot length on the north side of my yard that gets 8 hours of full sun.

The Iris roots will grow from the bottom of the rhizome during the winter months to anchor the plant. Then, around mid-January, two or three green pointed leaves will emerge from the soil and grow over the next couple of months to be upright, sword-like and about 16 inches long. 

Although it seems like the buds appear all of a sudden, they begin to grow in mid-February on long, thick stems usually taller than the leaves. Each stem has from only one to multiple buds that bloom on alternate schedules throughout the coming week or two. I sometimes stake the bud stems if they look top-heavy.  My Irises blooming from mid-April and continue in waves as long as weather permits. Remember, I said that I bought way too many. 

These plants love to propagate. Rhizomes should be separated about every two years. Each time I dig them I'm amazed at how many there are just under the surface of the soil.  It's a good idea to keep up with this duty. If I put it off, I feel like I practically need dynamite to break up the clumps. You might decide the rhizomes look like lobster tails too, because they are packed together on the surface of the soil like a pile of those crustaceans!

In the fall, cut the leaves to about 6 inches from the soil and leave the plant as is. Energy will be directed to the roots, where it's needed. The leaves will turn brown and dry and peel away. One of the reasons my Iris plants have been so neglected is that they have been virtually worry free to grow. To date I have had no pests or diseases. 

Again, if the soil is too moist the plants are susceptible to root rot and bacterial fungal problems. If planted in the shade they do not thrive. When the rhizomes get too compacted the plants will become spindly and weak. The iris borer can cause problems, but keeping the plants happy in their preferred environment will avoid the bulk of these problems. 

I highly recommend the bearded iris for those of you that would like green all year and splashes of vibrant colors in the spring.  Keep the plants thinned about every two years and you will be able to pass the surplus rhizomes to friends and neighbors to populate their gardens; then everyone has a chance at a colorful spring!

Informational links:

Missouri Botanical Garden: http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=f471

USDA: https://plants.usda.gov/core/profile?symbol=IRGE

During Napa County's shelter in place directive that protects everyone's health and safety, Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143.  Volunteers will get back to you after they research answers to your questions.

Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.

Photo credits: All photos by Mel Kendall