Fragile Frost Flowers
If you’ve been out exploring the countryside on a cold morning recently, you may have encountered the short-lived frost flower. Not really a flower at all, frost flowers are delicate and beautiful ribbons of ice crystals that form on the lower stems of several species of Missouri plants. They occur only after the first few hard freezes each year in late fall. Not only are frost flowers ephemeral because they only occur during a few days in the fall; they are also short-lived on the day that they occur, often melting quickly when the air temperature warms slightly or rays of sunlight fall on the delicate structures. I’ve received a few reports of frost flowers in recent weeks, but I expect that their season may have passed for this year.
Missouri plants that are known to produce frost flowers include: dittany (Cunila origanoides), stinkweed (Pluchea camphorata) and white crownbeard (Verbesina virginica). I don’t know what it is about these species that allow them to produce frost flowers. Perhaps their root systems are active later in the year than other species or their stems rupture in just the right way to extrude the ribbons of sap. Whatever the reason, frost flowers consistently restrict themselves to the stems of just a few species.
While the plants’ stems are ruptured by the freezing weather, the root system is still sending plant sap up from the warmer ground. The sap extrudes from the broken stem and freezes on contact with the cold air. As more saps moves up, it pushes the freezing ribbon of white ice crystals into odd-looking, folded ribbons that reminded someone of flower petals. Like snowflakes, I expect that no two frost flowers are ever identical.
Observers often report that they’ve lived in Missouri for decades but have never before seen such an occurrence. I guess it’s another instance of the requirement of “being in the right place at the right time.” It is encouraging to me that there are still new things to see in Missouri’s outdoors, something to offer for even experienced explorers of the natural landscape. Frost flowers are another reason to get out and explore, at a time when you might least expect to see something new.