PCIs - Breaking the Rules!

A bit of history...

Most gardeners recall "Grandmother's purple flags" as part of their childhood memories. While I'm sure my grandmothers also grew purple flags (I remember other colors), my earliest memories of irises are from the time, decades ago, when my family moved to the Seattle area. I recall seeing Dad dig some funny looking "potatoes" (I was rather young at the time), packing them in a plastic bag full of sawdust, and tossing the bag in the back of the Suburban for the trip. My recollection also includes Dad planting them six months later, their first bloom and his amazement at how well they had performed despite their relocation. Back then I didn't know how amazing it was that the rhizomes didn't rot away before they could be replanted, but maybe on a subconscious or intuitive level I recognized then how wonderful irises are, planting the seed (pun intended) for my current addiction to irises.

When I first moved out on my own, I was fortunate to have a small growing space. I was happy to take some of Dad's irises with me and was excited to order a few new rhizomes on occasion. I was quite satisfied with my 15 or so irises and felt that I had a nice range of color and flower styles. Then I discovered the King County Iris Society in the early 1990's and found a whole new world. Irises were not limited to Tall Bearded! There were Bearded irises that were only 4" tall and all heights in between up to the well-known Tall Beardeds. And better yet, Beardless irises too! I'd been minimally aware of Japanese Iris and Siberian Iris as landscape plants, but Spuria's and Louisiana's were new territory, as were the Pacific Coast Iris. After learning of these additional types of irises, my earlier interest became a fascination that in turn became something of an obsession. I went from a collection of a couple dozen bearded irises to well over a thousand irises. I wanted to experience them all! How could anyone have just one type?

Over time the collection started to shift more toward the beardless irises, in part due to maturing garden space and in part due to a growing realization that bearded irises were getting way too much attention. I wanted to support the "underdogs" of the iris world by growing and promoting more of the beardless varieties. As time has passed, my full-sun growing space began to shrink as the yard trees started maturing. It seemed logical that I start focusing on the Pacific Coast Irises, one of few irises outside of some species types that will perform well in part-shade. Of course, my growing passion for this particularly fabulous iris had nothing to do with my decision to specialize in it!

Iris-ly deranged....

Once it became quite obvious that my single-minded interest in Pacific Coast Irises wasn't just a passing phase, I began gathering every scrap of information I could about PCIs - books, articles, brochures, reprints from the Society for Pacific Coast Irises, online content, discussions with iris society members and the culture tips provided by various growers. I observed firsthand the cultural environment of local iris enthusiasts who shared my interest in growing PCIs, folks who had provided some divisions during my early attempts of growing these beauties. I also started becoming more mindful of the conditions and physical aspects of rhizomes shipped from growers, as well as how they were packed. Some arrived in pots, some bare root packed in various materials to retain moisture around the roots. Some leaves were trimmed and groomed, some not. Some rhizomes were no bigger than my pinky fingernail and others were the size of my thumb. Some had roots, some not. And some were single fans, several single fans or an intact division of two or more fans still attached to a "mother" rhizome.

My first few years of trying to grow PCIs were quite disappointing, even though I had been warned that growing them could be a challenge. A fifty percent survival rate of divisions or when transplanting seemed to be the norm for both neophytes and experienced growers; slightly better results were seen when potted divisions from commercial growers were shipped in the spring. I know now that in some of my earliest cases of loss it was because I did not yet understand the significant differences between PCIs and the other beardless types of irises. However, after being faced with these disappointing results for several years and not being content to just accept the 50% survival rate as the norm, I started trying some of the tricks of the trade I'd learned in my early years as a nurseryman and landscaper. Initially I just tried soaking incoming divisions in a vitamin B1 solution for several hours before planting. Over the next few years the survival rate increased to seventy percent! This was a bit of an "ah ha" revelation... What else might I do to improve the survival rate?

What I was taught....

When my interest in PCIs was first developing, I was told that divisions could not be made until new white roots start growing, and that new roots do not start growing until fall rains begin. While this is true to a certain extent, I've found that it is not necessarily always true. Although I am not a biologist or botanist, I do have reasonably strong botanical history having obtained Associate of Arts degrees in Landscape Design and Environmental Horticulture. I was also a Washington Certified Nurseryman for many of my years working as a Garden Center Manager. As I started to collate the PCI information I'd gathered, with the inclusion of my own observations, I noticed a somewhat surprising trend. The vast majority of the available information was based on growing conditions in California, the location of the most prolific growers and hybridizers of Pacific Coast Iris until recently. Comparing conditions in Pacific Northwest, an area that in my mind is defined as Washington and Oregon, west of the Cascades, to California is like comparing apples to oranges. While zone classifications are similar, the length of California provides a much broader range of conditions than the Pacific Northwest. I began to ponder what this might mean to those of us here in the Pacific Northwest growing Pacific Coast irises. I started taking a closer look at these factors and adjusting them for Pacific Northwest conditions:

Natural water: The Pacific Northwest rainy season typically begins in mid-September, where in California, rainfall doesn't typically start until mid-November. California tends to have less rainfall than the Pacific Northwest, especially during the summer.

Air temperatures: Pacific Northwest temperatures in the summer tend to range between 75 degrees and 85 degrees; winter temperatures can drop below freezing but generally range from 40 to 50. California temperature ranges are higher in both cases. Summers can get extremely higher. Occasionally Winter temperatures drop below freezing.

Soil temperatures: Pacific Northwest soil temperatures typically start dropping in mid-September (when the rainy season starts) and don't start rising again until mid-March. California temperatures don't start dropping until mid-November (when the rainy season starts) and start rising again in late January.

Fertilizing: Irises are heavy feeders and do require fertilizer for proper health. The type and timing is solely dependent upon local conditions and needs.

I've always wondered if there could be a photo-period response. In Seattle at summer solstice, the longest day of the year is about 16 hours. In California, the day length is 14 1/2 to 15 hours. Early bloom in Seattle starts in early April with about 13 1/2 daylight hours. California bloom starts in early March with 12 hours of daylight. So, in a very simplistic and unscientific determination, photo-period has no or insignificant effect.

Breaking the rules....

Taking all these factors into consideration caused me to change the way I grow Pacific Coast Irises, breaking the established rules. I prefer slow-release fertilizers as they reduce maintenance needs and provide an easy way to keep all the plants growing well. Due to the numbers of plants growing in a small space (we don't have acreage!) and the compost we use, nitrogen deficiency quickly becomes a problem. Scott's Starter Fertilizer has provided slow-release as well as micro-nutrients quite effectively. We've found that our PCIs do not go into a semi-dormant state during the summer since we tend to have moister conditions as we water once a week to keep the rest of the yard healthy. We've not noted any harm to the PCIs and granular fertilizing is rather useless if water isn't available to break it down and make nutrients available to the plants. Lack of dormancy and the extra nutrients have been a factor in "new" roots developing as early as mid-August. Divisions have been successfully pulled from mature clumps and transplanted with little or no sign of stress. Similarly, full clumps have been moved intact from one location to another and successfully moved in mid-August. I always soak my divisions in a Vitamin B1 solution for a few hours before planting; full clumps are simply moved with little or no root disturbance and then soaked in place. Mulching after planting is highly recommended!

Another aspect of my rule breaking is apparent when it comes to starting PCI seed. My research indicated that the seed needed to be hung in a nylon baggy in the toilet tank for several weeks, or potted up and kept refrigerated for several days. This sounds like way too much work, so I thought I'd try an easier way... so, in October the seed was placed between paper towels kept moist with a Vitamin B1 solution and left on the kitchen counter, and then planted in a pot and kept in a minimally heated greenhouse. I saw seedlings emerging within 6-8 weeks and have consistently gotten the same results for the past several years. The seed I used was my own, freshly harvested one or two months prior, so it may be that this method would not be as effective with seed 2 or 3 years old. I may have to get some and try, just for comparison.

These practices work well for me in my particular growing circumstances. You may need to find your own way!