Beautiful Iris

by Janet Krupka

Late spring is when my yard seems to look it's best and this year's lack of rainfall did not hinder some of my favorites from performing well, especially the irises. Of the 300 types of Iris, all have three inner petals and three outer petals. There's an Iris that can be grown in every temperate region. I have three types in my yard; bearded, douglass, and a mystery.

The bold tall bearded iris (Iris germanica) is known for the fuzzy caterpillar like hairs on the falls of the outer petals and have been bred in a rainbow of colors. Their specialty rhizomes are not safe from predators in my yard, so I grow them in a large pot but they're pretty happy with that. Even so, I think that a squirrel or other rodent got my only reliable repeat bloomer, a white fragrant “Immortality” which didn't make an appearance last year but I may have forgotten to add fertilizer in time. A slow release pellet product with the addition of organic 0-10-10 to encourage bud set early is what my prima donnas like best, but they're a little crowded and need to be divided this August. An easy job since the rhizomes are sitting almost on the surface of the soil.

To divide: remove them, separate with a sharp knife, cut each leaf fan down to 6” and replant 18-24”apart if in ground (with all fans facing out if in pot) and cover with 1” of soil. All Iris are divided in a similar manner, in clump forming types, remove the older middle sections, cut all roots to 3”, fans to 6” and replant younger rhizomes just below the surface in new rich, good draining soil.

The Iris douglasiana or Douglas Iris is a common coastal wildflower found from Southern Oregon to Central California and occasionally inland. This dainty but rugged native adapts well to gardens forming neat clumps of foliage and a reliable show of blooms. Though sometimes considered a nuisance to farmers because cows do not like the taste, I find them delightful, unfussy and long lasting in my border.

The most prevalent Iris that I grow is a mystery to me. Like most of my “lost and found “ yard, I inherited it, and since there's so many types of Irises to begin with- I am not sure what to call this vagrant turned resident. At one time I thought it was a reticulated (Iris reticulata) because the flowers are similar but it is much too tall (at knee high) to be that tiny early blooming gem. No, my nameless sport has swordlike grassy mounds all year with plenty of flowers and bright orange berries seeds in the fall that hang on-unless the birds disperse them to and fro. The flowers are not flamboyant like many of its relatives, being a soft dusky purple, but they will grow without water or care and you can't ask for much more than that. Out of all the Iris I have grown, these subtle beauties are my favorite.

Master Gardeners are following recommended social distancing guidelines that keep everyone safe, 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: Janet Krupka

References:

UC IPM-Iris http://ipm.ucanr.edu/PMG/GARDEN/FLOWERS/iris.html

The Jepson Herbarium

-Iris germanica https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29198

-Iris douglasiana https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=29188

Pacific Bulb Society-Iris https://www.pacificbulbsociety.org/pbswiki/index.php/Iris