Ice Flowers

contributed by Glenn Kotnik

Late November had been warm and pleasant. Yet when I was awakened by the guttural vocalizations of my boy Flint, I sensed change. The air in my cabin crackled with crisp chill as though the moisture in the air had crystallized and precipitated while I slept. Flint knew we were in for adventure and he couldn’t wait to get me moving. Soon I was warming my fingers on a mug of hot coffee and my toes in front of the fire in the wood stove. My majestic ash trees, all dead not long after the arrival of the ash borers, were still good for one thing.  I was grateful for the many years of sunlight energy stored in their wood being released as it burned.

Flint was insistent on exploring the woods so I loaded him and the other maniac into my Jeep and we drove a short way on gravel roads and parked at the head of a favorite trail. They knew the way and were impatient as I searched the frost covered woodland understory for signs of life.

The solubility of water in air depends on the temperature of the air. When warm humid air very suddenly mixes with colder air, the air can become supersaturated with water vapor. Supersaturation is unstable and sudden precipitation of ice crystals on available surfaces will occur. This was the case with the needles of crystalline water I found on many surfaces in the forest understory that morning. Moss, logs, mushrooms all had glittering deposits of crystallized moisture on their surfaces. The mushrooms were especially interesting, they may have been Galarina marginata, one of the few species beside the Amanitas to contain the deadly hepatic toxin α-Amanitin.

Another crystal formation caught my eye, curled, twisted and contorted, reminiscent of a ram’s horn.

It had been almost 20 years since I had last seen ice flowers, many of them, and in a large group. Now I saw only a single one.  The spot I had seen ice flowers many years ago was only a few miles away so we hiked back to the truck and drove to the location where I hoped I once again find these rare formations. After a brief hike, there they were, the exact location I remembered. Why? What was special about this location that these rare ice flowers formed there?

The ice flowers were up on a very steep slope.  It was all I could do to crawl up the incline by hanging onto saplings with one hand.  With my free hand I took a few cellphone photos.  No chance of bringing a real camera up there. And by the time I returned with the camera, these evanescent blossoms would have returned to the liquid state.

It took a bit of research to get the story of how ice flowers form, why they are rarely seen, and why so often in the same location. They grow from the dry stems of only a few plants, 40 worldwide I’ve learned. In the midwestern United States only Dittany, Cunila origanoides, a wonderful smelling member of the mint family, seems to host ice flowers. After a spell of wet rainy weather, when the air and ground are saturated with moisture, a sudden hard freeze will force watery sap up from the roots and stems of Dittany and out through longitudinal cracks in the stems. This sap freezes suddenly on contact with the cold air.  The result are wide, thin sheets of ice which curl into phantasmagorical forms resembling flowers.

I took a few of the dried stems of Dittany back to my cabin with me and photographed the dried plants. Beautiful plants, with very aromatic leaves. Crushing the leaves releases an aroma almost exactly like the Italian seasoning oregano. Should I? Yes! I put a can of tomato sauce into a pan and added a couple generous pinches of crushed Dittany leaves.  After some time simmering, I tasted a spoonful.  Yuck! Bitter.  So much for that idea.

Later I did a low power photomicrograph of the dry Dittany stems. The longitudinal cracks are clearly visible. If cold moisture were suddenly forced out from these cracks into subfreezing air, one can visualize the formation of ice flowers. But only under certain specific conditions of soil saturation, air saturation with moisture, and sudden temperature drop.

According to Indiana botanist Mike Homoya, Dittany is the only plant in the Midwest that seems to produce ice flowers. He calls Cunila oreginoides a “frostweed”. Only about 40 such species of frostweed species are known worldwide.

Now is the beginning of the ice flower season.  If there is a sudden cold snap after a warm period of rain, go to the spot where you saw the beautiful flowers of Dittany in late summer. With luck you’ll find them.  It’s like hunting mushrooms. But I don’t recommend making spaghetti sauce!

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