NATIONWIDE — Frostweed, Verbesina virginica, a butterfly favorite, blooms in late Texas summers, the hottest part of the year, and continues blooming until frost.
This biennial, also known as white crownbeard/Indian tobacco/tickweed, ranges in height from 3 to 6 feet tall. The plant was named Frostweed because of this unique characteristic of producing intricate ice formations from its stems.
The Texas native is likely what you’re seeing as only a few species of plants are capable of producing these icy creations, more generically referred to as “frost flowers.”
Aside from Verbesina virginica, yellow ironweed (Verbesina alternifolia) and Helianthemum canadense as also known to produce “frost flowers.”
According to an article by Scientific American, evidence “frost flowers" can be found in a January 12, 1833, letter printed in Philosophical Magazine, in which John Herschel describes going for an early morning walk several winters before and noticing "a remarkable deposition of ice around the decaying stems of vegetables."
A few days later, he found a similar strange ice formation, this one seeming "to emanate in a kind of riband- or frill-shaped wavy excrescence."
Herschel's letter is one of the earliest recorded observations of frost flowers.
Frost flowers live a short life, and disappear quickly on the day they occur, melting like frost when the air warms or rays of sunlight fall on the delicate structures.
Scientists are unsure why only these plants produce crystal ice patterns into ribbons or clusters that resemble flowers, and also why only certain types of plants are affected.
One theory is that their root systems stay active pulling up moisture from the soil, even though the upper parts of the plants go dormant in autumn.
Another theory is that the stems rupture and crack in just the right way so sap oozing out forms into wide ribbons that freezes into the ice patterns.
Frost flowers often appear on plants when a sudden cold snap follows conditions that have kept soil moist and warm.