Nature: Delicate frost flowers are Nature's answer to ice sculptures

A frost flower formed on a dittany plant/Jim McCormac

Nature: Delicate frost flowers are Nature's answer to ice sculptures

Columbus Dispatch
January 1, 2022

NATURE
Jim McCormac

Saturday, Nov. 19 dawned crisp and cold. I had stayed at the Shawnee Lodge in Shawnee State Park (Scioto County) the preceding evening to attend a meeting. The largest contiguous forest in Ohio, Shawnee State Forest, surrounds the lodge, and there are about 70,000 acres of wildlands to explore.

I left the lodge before the crack of dawn. Within a minute of departing, I was pleased to see a gray fox saunter across the road. Gray foxes have become much scarcer in recent decades, making sightings of these superb cat-like canids especially noteworthy. Perhaps the elegant fox was an omen of good things to come.

My primary mission, however, involved inanimate objects known as frost flowers. For many years, I had heard about these icy ephemera but had yet to clap eyes on one. Today would be the day.

The day before had been fairly warm, with temperatures in the mid to high 30s. Scattered rains in the preceding days had dampened the ground. When I headed out in the morning, the temperature had plummeted to 12 degrees. The conditions were ripe for the formation of frost flowers.

A frost flower is an incredibly delicate ice sculpture that forms around the bases of certain plants. In southeastern Ohio, the primary producer of frost flowers is a little mint called dittany (Cunila origanoides). It is common in Shawnee State Forest.

I headed for a remote ridgetop with well-drained sparsely vegetated slopes - perfect dittany habitat. I knew from experience that dittany abounded at this site. Within seconds of arrival, I saw what looked to be shards of whitish Styrofoam dotting the ground. Finally – the fabled frost flower!

While frost flowers don’t look like much from afar, up close they are spectacular. Wafer-thin icy curlicues resembling ribbon candy cling to the bases of the dittany stems, forming all manner of sculptures. No two are alike.

One must be gentle around frost flowers. I quickly learned, when trying to pull intruding vegetation aside, that even the mildest perturbance would shatter the frozen rime. The observer must look, not touch, to avoid instant destruction.

Frost flowers form when mostly senescent host plants are still drawing water upward into the stem. Cold air freezes the liquid in the stem, creating longitudinal fissures. New water is forced from these cracks, creating the fantastic icy artwork.

The first cold snaps of mid- to late November is prime time for frost flower formation. Not all suitable plant hosts will form them the first frosty night, so seekers might have a few shots at finding the icy “flowers." Searchers need to get out early. The first sun rays quickly melt the frozen objets d’art.

Adventurous gardeners might consider planting a frost flower garden. In addition to dittany, other native (or nearly so) Ohio flora known to produce frost flowers are Canada frostweed (Helianthemum canadense), white crownbeard (Verbesina virginica), and wingstem (Verbesina alternifolia).

Canada frostweed will be tough to find in the nursery trade. The delicate little member of the rockrose family isn’t common garden fare. The other two are easily obtained, but purists can take note that although the southern white crownbeard occurs as far north as northern Kentucky, it hasn’t been documented as a native in Ohio.

As the morning warmed and the frost flowers liquefied, I moved on to other photographic pursuits. And lo and behold, around 10 a.m. I spotted and photographed a female bobcat with two kittens. They were the subject of my Dec. 4 column.

Apparently, that gray fox was indeed a good omen.

Naturalist Jim McCormac writes a column for The Dispatch on the first, third and fifth Sundays of the month. He also writes about nature atwww.jimmccormac.blogspot.com.

Frost Flowers

 

This is a showy little mint known as Dittany (Cunila origanoides). It is a southern species, and Ohio is at the northern limits of its range. Dittany ranges across the southeastern and eastern portion of the state - the hill country.

Little pinkish flowers are held in axillary fascicles. Dittany blooms in late summer. The preceding image was made on August 23, 2014, in Athens County, and the above shot dates to August 24, 2019, from Scioto County.

Dittany is habitat-specific: it favors poor often rocky and acidic soils in well-drained sites. Sparsely vegetated roadbanks along or near ridgetops are good places to look.

The little mint is well-known for producing the subject of this post: frost flowers. Ephemeral in the extreme, one's window to seek the fascinating phenomenon of frost flowers is quite brief. I've long known of frost flowers but had not managed to catch up to them until last Friday, November 19. I was at the lodge at Shawnee State Park in Scioto County for a meeting and stayed over that night. The day had been relatively warm and the ground was damp due to previous rains. That night the mercury nosedived, and when I went afield at dawn the following day it was 13 F. Perfect for finding frost flowers and that mission was foremost on my list.

After a wonderful encounter with a Gray Fox - no photos, unfortunately - I soon arrived at a ridgetop lush with Dittany. And in no time clapped eyes on frost flowers. The one above is among the first that I saw.

Frost flowers are formed when the plant's roots are still forcing liquid upwards into the stem, and soil temperatures are warm enough that water has not yet frozen. A sudden overnight drop in temperatures below freezing is then required to produce the beautiful ice formations. As the liquids are forced into the old brittle stems, the water freezes, expands, and cracks the stems. Water is then forced outwards and freezes into bizarre formations on the lower stems.

Another, more cylindrical frost flower. No two are alike. Frost flowers are very white, and it might be easy to pass them by as pieces of debris - Styrofoam, or something similar. But because of their whiteness, they stick out like sore thumbs in the brown leaf litter of early winter. Once attuned and on the search, a frost flower hunter will have little difficulty finding the quarry, as long as the conditions are right, and the hunter is out early. Once the first sun rays strike them, the frost flowers quickly melt away.

The gossamer rime is exceptionally fragile, as I quickly learned. Even slight contact with a frost flower, say, attempting to pull a leaf away and bumping one, often shatters it. One must work gently with these icy subjects.

The striations and banding patterns of frost flowers are fantastically varied and ornate. They often resemble ribbon candy.

This was one of the larger frost flowers that I encountered. While shaped differently, it was near the size of a pop can. Others were perhaps the size of a roll of pennies.

A hollowed-out cup-like frost flower. That's the Dittany stem that formed out, spanning the top of the "flower".

This Saturday was a very good day afield - nearly all of it serendipitous. I usually have a fairly concrete plan of attack when going afield. In this case, when I headed down on Friday my plan was to look for and photograph birds the following morning. Then, when I realized how the temperatures would be nose-diving that night, my focus shifted to frost flowers. The Gray Fox first thing was a good omen. Within 10 minutes of that sighting, I had located my first frost flowers, and went on to find several dozen. Then, around 10 am I encountered the Bobcat family that is featured in the previous post.

Not a bad day, and I hope to time things right for next year's frost flower crop.