Frost Flowers

If you've been out and about early in the morning, you may have seen what looks like litter or balled-up paper in a field or next to a road. If you look closer, you would see that these things are not litter, but icy wings squeezed from plants. These are called frost flowers, although one old-timer called them "Jack Frost" and as a child he would rush to eat them before they melted! At Blanchard we have seen them all along the creek and down near the campground this past week.

Frost flowersare netiher frost nor flower. According to the Missouri Department of Conservation, they form when moisture already inside the stem of a plant freezes. One of the properties of water is that it expands when it freezes. The skin of the plant stem splits under the pressure of the expanding ice. Because of the cell structure of the plant’s stem, the splits occur in tiny vertical rows. Capillary action in the plant’s veins pumps the moisture out through these minuscule cracks like translucent ribbon candy. As crack after crack yields a layer of ice, the total effect resembles the many layers of a flower petal. Air bubbles trapped in the ice makes it appear frothy white.If the air is cold and still when a frost flower forms, the ice layers push straight out into large silvery feathers. When conditions cause the leading edge of ice to thaw slightly as it forms, the frost flower will curl inward around the stem like cotton candy on a stick. Each layer of ice is so thin that the total frost flower is almost weightless and will shatter like glass if touched.

Frost flowers occur in many parts of the world and all across Arkansas and Missouri. However, only a few species of plants produce frost flowers, and the formations never occur in exactly the same manner from one year to the next, or even from one night to the next. Some plants continue to split and freeze, so that it may "bloom" more than once.

Native Ozark wildflowers that mature late in the year, such as yellow ironweed (Verbesina alternifolia) and white crownbeard (Verbesina virginica), are good frost flower prospects. In fact, white crownbeard is commonly called frostweed. It has long, toothy oval leaves and a crown of small white flowers. Reaching a height of up to seven feet, white crownbeard grows in open woods, valleys and streamsides south of the Missouri River.Yellow ironweed grows statewide in moist, lowland woods and along streams. The plant is similar in appearance to white crownbeard, but it produces numerous ragged, yellow flowers. Stems of these plants are still green and tender in late October, and have a pithy core that can hold a lot of moisture–key factors in frost flower formation. Plants that already have died and turned dry and brittle before the first hard freeze will not produce any frost flowers.

Weedy fencerows, stream banks, roadside ditches, city weed lots, weedy gardens and moist, open woodlands all are potential frost flower sites. Because high plant moisture content and exposure to sudden hard freezes produce the most abundant frost flowers, low-lying Ozark "frost hollers" are prime locations. It helps if we've had a wet year, like the one we're having this year.

So if you happen to be out and about early, you may catch some of these magical, ephemeral formations. But go early - once the sun hits them, they're gone!