What Makes it Difficult?
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| Sino-siberian iris, 'Dotted Line' (Lorena Reid, R. 1991). Image from Cascadia Iris Gardens |
I know that the plants I love make use of this cold and snow cover for their dormancy. I try to reassure myself that the newly planted irises wont be damaged by the cold. The blanket of mulch I put down in October should help moderate the wild swings in air temperature. But I wont know until springtime.
What makes it difficult? Where did that title come from? Why ask the question in the middle of a post?
Difficult in gardening can mean a hundred things to a hundred gardeners. That's partly why I have a sidebar that says that this blog isn't specifically for beginners (or advanced growers). Everyone comes with their own experiences. Rather than adhering to the idea of certainty, I prefer gardening closer to the edge of chaos. What might work? There's a fair bit of risk involved in that idea.
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| 'Black Garnet' ( Lorena Reid, R. 1996), Image from Cascadia Iris Gardens |
Gardeners are usually familiar with the idea of zones. The USDA puts a tremendous amount of work into determining hardiness zones throughout the US. "The map is based on the average annual extreme minimum winter temperature, displayed as 10-degree F zones and 5-degree F half zones." Link to USDA hardiness map.
I think considering us 5b in years past was optimistic. Trying to imagine that we might be 6a now is even harder. Here's why I think this is a difficult assessment. Seasons, climate and weather. We use the words as though we understand them. Seasons relate to the slow tilting of our planet... not to what giant blow up ornament is flopping in someone's yard. Climate is the long term weather pattern (usually an average over 30 years) for a given location. Weather is in the moment; is it snowing? what is the temperature now?
Yesterday I was reading about folks complaining that there was reason to worry about climate change because a warmer winter would mean lower heating bills. I also read folks commenting that there couldn't be global warming because it was cold here. These sorts of arguments pop up every year, right about this time of year. The determined ignorance is disheartening. Let's talk about hardiness instead.
So, zone 5b seemed inaccurate before and 6a seems wildly inaccurate now. Why? Well... the critical word in the photo above is average. Not just the peak cold temperature. I am not a statistician. I let my kiddo explain statistics to me. Averages over time. A LOT of time. The bigger the span of time, the flatter that average starts to look. But that last line in the photo above shows that over an eleven year period, that average temperature has increased 4°F.
Why does that matter? Shouldn't warmer = better?
Rather than drawing this out, I want to use an iris variety to explain why it matters. The irises illustrated earlier in this post are sino-siberian irises. Sino-siberian irises belong to the subseries Chrysographes.
The Sino-siberian iris are composed of 7 species. Two are yellow-flowered and these include I. forrestii and I. wilsonii, both from western China. These two appear quite similar but the standards of I. forrestii are stiffly upright while those of I. wilsonii are held at a 45 degree angle. The flower stems of I. wilsonii are about the same length as the leaves while I. forrestii has stalks taller than their leaves. Between the two species, I. forrestii blooms about 2 weeks earlier than I. wilsonii. Generally, I. forrestii is of smaller stature than I. wilsonii. (Todd Boland, https://davesgarden.com/guides/articles/view/2668)
Most of the folks who grow sino-siberian irises start out growing easier, more adaptable irises.What makes these irises difficult to grow in most parts of the country is their particular climate needs. They need steady moisture throughout the year but most critically from the end of winter until the start of fall rains. This would jive with their historical habitat in the mountain valleys of China, Nepal, India and Tibet, freshened by snowmelt all summer long. When I would come across these high altitude valleys up in the Rockies, it was such a surprise. Bright rich verdant grasses and wildflowers when just a few meters above would be almost nothing but conifers and scrub. They were treasures, especially in the summer, with their moisture held like water in a cupped hand.
Back to the question... what makes it difficult?
Climate change. That's the short answer. Longer answer has to do with multiple variables. Water that falls when I plant is able to take it in is good. Water that falls on sodden soil is flooding. Water that freezes into a solid block isnt absorbed by the soil readily. Ice that thaws and refreezes rapidly tends to crush anything tender. Each time it refreezes, some of that water is lost. Evaporation happens in the winter too. Snow acts more like a soft blanket, insulating, slowly releasing water into the soil. Gentle. What I am concerned about is the extremes. We are seeing so many more strong vacillations in the weather that it throws off the normal behavior of the plants. A plant that breaks dormancy early in the season because the weather is warm in February is in for a rude awakening in March when the temperature slams back down way below freezing again and again.
Anyone who grows fruit is familiar with late frosts damaging blossoms and ruining the year's crops. I am starting to see indications of this throughout the garden. I saw it last year with my peonies especially. Many had started forming buds (just tiny things) in the warmth of April and then we saw a wicked cold snap at the end of the month. Those buds froze. That was it for the year's flowers on that plant.
Which makes me wonder about these sino-siberian irises. Can I figure out a way to insulate them from these wild swings in temperature so that they are protected from the thaws that seem to be happening with greater frequency? I have always mulched my beds, but I might need to think about building the garden with greater emphasis on creating microclimates specifically designed to push longer dormancy. We all want to see flowers as soon as possible in the season, but maybe that comes at too great a risk? And that's just the winter difficulties. Summer difficulties I'll hold off until we get closer to the relevant season.
What makes these irises worth the effort? For one thing, they are different. They have a very different style to their growth. Some of the colors are so rich and saturated as to seem almost inky.
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| 'McKenzie Bruiser' ( Lorena Reid, R. 2001). photo from Cascadia Iris Gardens |
When I look at that rich color and intense form, I feel compelled! I want to plunge into that inky depth. I can't wait to see a whole clump of these in person!
This year, I was sent a package of seeds from Bob Hollingworth and the Siberian Iris Society. In the package were seeds from hybrid siberian irises (2n=28), crosses of all sorts! There were also seeds from these sino-siberians (2n=40). I am so excited to start these seeds. Part of me is scared that it will be a waste of seeds, time, etc. But another part thinks that it might be incredible! These irises aren't offered for sale around here. They aren't common enough to be found in stores or garden centers. But if the seeds survive, and the seedlings thrive... then we'll have something to talk about!
So far, I have learned that this garden is wet and cold. In the summer it is hot and bone dry, unless it rains non-stop from July into September. It almost feels like a proving ground designed to kill less hardy plants. It will be interesting to see how the changes in ecology of this garden potentially affect the range of plants we can grow. Can we protect these more difficult plants until they are able to thrive? That's what makes it difficult.
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