Ice crystals sometimes build one on top of the other to form frost or ice flowers, a natural phenomenon that happens in early winter, when the ground is not already frozen. Image credit: Slomoz
Frost or ice 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.
Frost flower formations are also referred to as frost castles, ice castles, ice blossoms, or crystallofolia.
The formation of frost flowers is dependent on a freezing weather condition occurring when the ground is not already frozen. 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.