Friday, November 25, 2022

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.


Chris said...

Thanks for this post, Jim! I hadn't encountered Frost Flowers before and am grateful for the images and the description about how they come to be - very interesting!

Susan said...