What is a frost flower?

A frost flower is not truly frost nor is it a flower. The ribbons of ice form from sap slowly freezing as it oozes from a living plant during a period of freezing temperatures.

The night of Nov. 6 was calm. A cold front brought light rain a day earlier making everything wet. Nighttime temperatures fell to a few degrees below freezing. Lingering moisture on low-lying plants turned to frost, alerting me to the possibility that I could find a frost flower.

Frost flowers are often larger and more dazzling than the one I'm showing here, but seldom does one show more clearly how this natural phenomenon forms. The bark of this goldenrod's stem burst open as it froze. The sap of the plant ran slowly out, freezing as it did so. You can easily see the broken skin of the goldenrod.