Have you ever heard of a frost flower? Ever see one?
In Kentucky, frost flowers can be found among tall weeds and plants located near a field or prairie. Likely candidates for frost flowers include wingstem, ironweed, goldenrod, ragweed and other herbaceous plants boasting a thick, hollow stem.
Frost flowers can be found pretty easily throughout the state, especially during a heavy frost or freeze in spring and fall when air is cold and the plants have a high moisture content. In fact, certain conditions need to be just right for the formation of frost flowers:
- freezing air temperatures
- soil that is moist or wet but not frozen
- a plant's stem that has not been previously frozen
Understanding how a frost flower forms requires conjuring up some middle school science. Through a process called capillary action, water is drawn upward from the ground and into a plant's stem. As the water freezes, it expands and creates microscopic cracks. Then, when the water vapor exits those cracks, it freezes, emerging as paper thin "petals" of ice.
Because water is continually being drawn up into a plant's stem, the process of cracking and freezing can result in many petals. The size of the cracks determines the shape of the petals, resulting in unique flowers of all shapes and sizes!
Similar to snowflakes, no two frost flowers are alike.
You can find frost flowers at many of The Nature Conservancy's Kentucky preserves, including along the fields located at the Brown/Crutcher/Wallace Nature Preserve and at the Dupree Nature Preserve between where the parking lot and the trail enters the trees.
The best time to search for frost flowers is early in the morning, before the sun rises, on a day with freezing air temperatures and unfrozen ground. But remember, you can't pick the flowers as your warm hands will melt these masterpieces of nature. Bring a camera instead!