Frost Flowers: A Winter Wonder

by Laura Lemmon, Extension Master Gardener

While few flowers are visible when nighttime temperatures drop below freezing, a different type of "flower" can be observed on early morning walks. This phenomenon, known as a "frost flower" or "ice flower," occurs when moisture in certain herbaceous plants freezes and causes the stems to split vertically. As the stem splits, the exposed sap is pushed out in ribbons, which then freeze into ice crystals. Frost flowers are most likely to form when the air temperatures are very cold, while the soil remains unfrozen.

Three of our native plants have demonstrated the ability to form frost flowers when environmental conditions are met.

Verbesina alternifolia is commonly known as Wingstem. This tall plant's bright yellow summer flowers may be seen in forests, low meadows, and clearings.

Cunila origanoides, is commonly known as American Dittany or Wild Oregano. Dittany likes well-drained soil and has purple blooms from late summer into fall.

Verbesina virginica, is commonly known as White Crownbeard or Frostweed. This tall, dappled, shade-loving plant blooms with white flowers in the summer months.

All three species are deer tolerant and support insect and pollinator populations with clusters of colorful flowers. They may also provide a bonus in cold weather if their stems remain after blooming with white ribbons of ice.
Resources
University of Missouri - Integrated Pest Management:
https://ipm.missouri.edu/meg/2018/10/iceFlowers/
Illinois Extension - College of Agricultural, Consumer & Environmental Sciences:
https://extension.illinois.edu/blogs/naturalist-news/2021-01-02-natures-current-event-frost-flowers



frost flowers




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