Frost Flowers

Not really a flower

If you’ve been out exploring the countryside on a cold, late-autumn morning, you may have encountered the short-lived frost flower. Not really a flower at all, frost flowers are delicate, beautiful ribbons of ice crystals that form on the lower stems of a few species of Missouri native plants.

They appear in late fall

Frost flowers occur only in late fall after the first few hard freezes and while the ground is still warm. Their season is brief, and they disappear quickly on the day they occur, melting like frost when the air warms or rays of sunlight fall on the delicate structures.

How they form

While the plants’ stems are ruptured by the first hard freeze, the root system is still sending up plant sap from the warmer ground. The sap pushes through the broken stem and freezes on contact with the cold air. As more saps moves up, it forces the freezing stream of white ice crystals into ornate, folded ribbons that look like petals, puffs of cotton candy, or snarls of white thread.

Missouri plants that produce them

Missouri plants known to produce frost flowers include dittany (Cunila origanoides), stinkweed (Pluchea camphorate is not widespread in Missouri) and white crownbeard (Verbesina virginica). Scientists don’t know what it is about these species that allow them to produce frost flowers. Perhaps their root systems are more active later in the year than other species, or their stems rupture in just the right way to force the ribbons of sap. Whatever the reason, frost flowers only appear on the stems of a few species.

Get outside early on late fall mornings

Even experienced nature explorers have never seen frost flowers. This is because you have to be in the right place at the right time. Get to know Missouri’s frost-flower plants and find places where they grow naturally. Then keep your eye on the calendar and the weather. When it starts to frost in the fall, plan to get out early and visit the places where you’ve seen frost-flower plants growing. Don’t forget your camera. If you’re lucky, you may snap a few pictures before the ice ribbons melt in the morning sunlight.

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