Natural Ice Sculptures
Crystallofolia are natural ice sculptures that can be found in the fields and forests in early fall or winter.
These sculptures are delicate ice formations that form from water emitted along a stem, most commonly near the base of dormant plants during a hard freeze in late fall/early winter.
Relatively few plant species are known to exhibit crystallofolia, the most common varieties are Cunila origanoides (stone mint, common dittany), Helianthemum canadense (frostweed), Verbesina virginica (frostweed, iceweed), Verbesina alternifolia (wingstem, golden ironweed).
These natural ice sculptures are commonly called ice flowers, frost flowers or hair ice. They form when there is freezing weather and the ground is not frozen yet. The water in the sap of the stems of plants freezes and seeps out creating the ice sculpture.
Notice how the ice can create a “swirling” shape. This can also happen on wood where the bark has been removed by a similar process. The ice has a “hair” looking shape in this situation. See pictures below.
Frost flowers is the name commonly given to a condition in which thin layers of ice are extruded from long-stemmed plants in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers.
The petals of frost flowers are very delicate and will break when touched. They usually melt or sublimate when exposed to sunlight and are usually visible in the early morning or in shaded areas.
The sap in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem. Water is then drawn through these cracks via capillary action and freezes upon contact with the air. As more water is drawn through the cracks it pushes the thin ice layers further from the stem, causing a thin "petal" to form.
To see more amazing photos of this phenomenon check out this compilation of natural ice sculptures.
Hair Ice is ice that grows outward from the surface of the wood, as super-cooled water emerges, freezes and adds to the hairs from the base.
In the case of woody plants and tree branches, it is squeezed through the pores of the plant by capillary action forming long thin strings of ice that look like hair.