A frost flower or ice flower is formed when thin layers of

ice Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaqu ...

are extruded from long-stemmed

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

s in autumn or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "

petals Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usually ...

" that resemble

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

Types

Frost flower formations are also referred to as ''frost faces'', ''ice castles'', ''ice blossoms'', or ''crystallofolia''. Types of frost flowers include

needle ice Needle ice is a needle-shaped column of ice formed by groundwater. Needle ice forms when the temperature of the soil is above and the surface temperature of the air is below . Liquid water underground rises to the surface by capillary action, a ...

, frost pillars or frost columns, extruded from pores in the soil, and ice ribbons, rabbit frost or rabbit ice, extruded from linear fissures in plant stems. The term "ice flower" is also used as synonym for ice ribbons, but it may be used to describe the unrelated

phenomenon A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried ...

window frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a ga ...

as well.

Formation

The formation of frost flowers is dependent on a

freezing Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid ...

weather condition occurring when the ground is not already frozen. The

sap Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a separ ...

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 Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of, or even in opposition to, any external forces li ...

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. 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. Examples of plants that often form frost flowers are white crownbeard ('' Verbesina virginica''), commonly called frostweed, yellow ironweed (''

Verbesina alternifolia ''Verbesina alternifolia'' is a species of flowering plant in the family Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. ...

''), dittany (''

Cunila origanoides ''Cunila origanoides'', with the common names stone mint, frost mint, dittany, and American dittany, is a perennial late-summer-flowering subshrub with small purple flowers that is native to the central and eastern United States. It belongs to ...

''), and ''

Helianthemum canadense ''Helianthemum canadense'' or ''Crocanthemum canadense'' (known as longbranch frostweed, Canada frostweed, frostweed, rock frost, frostplant, or frostwort) is a species of rock-rose (Cistaceae), native to eastern North America North ...

''. File:BurstBark.jpg, Example of the hydraulic power of capilliary freezing File:Frost-Flower-4.JPG, Frost flower closeup File:Frost flower Oct 2017.jpg, Frost flower on a yellow ironweed stem in southern Missouri File:Frost flower on dittany.jpg, Frost flower on common dittany (Cunila origanoides) in NW Arkansas

References

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External links

Website about frost flowers
{{ice Frost and rime Hydrology Water ice Plant physiology

Types

Formation

See also

References

External links