Nature Finds: Ice Flowers

TACF chapter members are a crucial asset toward our mission to rescue the American chestnut tree. In addition to their invaluable volunteer work, we also appreciate their diverse interests and expertise. For example, Indiana Chapter President Glenn Kotnik is not only passionate about American chestnut restoration, he is also a skilled and knowledgeable nature photographer! Please enjoy the following educational piece by Glenn in which he explains the phenomenon of ice flowers as part of an exhibit for the Lake Hope State Park Nature Center in southeastern Ohio.

Another photo of ice flowers, courtesy of Glenn Kotnik.

“A pleasant surprise on a frosty late autumn or early spring morning!

Ice flowers may be overlooked by a hiker who is not searching for them, they are often hidden by vegetation along trails. Also known as frost flowers, they only form when weather is above freezing and the soil is wet, and there is a sudden hard freeze as the temperature drops. Liquid sap in the roots and lower stems of certain plants begins to freeze and is forced out through cracks in the bases of the stems. As the extruded sap hits the frigid air it immediately freezes into fantastic shapes resembling plant flowers. Indeed ice flowers are not actual flowers of flowering plants, ice flowers are water, ice, that’s all.

‘Certain plants’ is key. In the Midwest and the Zeleski State Forest area, only one plant is known to produce ice flowers: Cunila origanoides, also known as Dittany, a member of the mint family Lamiaceae. Like most members of the mint family, the crushed leaves of Dittany have a wonderful fragrance, very much like oregano or Wild Bergamot, which are also Lamiaceae.

Why are ice flowers limited to just Dittany? To answer this question, I performed microscopy on the dry stems of Dittany. There clearly were longitudinal cracks in the lower stems of Dittany through which sap could be extruded, and in frosty weather the sap could freeze into ribbons of ice, hence ice flowers!

Dittany is easier to spot in the summer when its tiny blue flowers can be seen along woodland trails. Keep the location in mind and return when the plants have tried up and there is a sudden hard freeze, you may be rewarded by the sight of ice flowers.”