Frost Flowers: One Name,Two Different Things    

Dr. James R. Carter, Professor Emeritus

Geography-Geology Department

Illinois State University, Normal IL 61790-4400


What is in a name?  When people see unusual displays of ice in nature they create names to identify what they have found.  There are at least two types of ice formations that people associate with flowers.  Then they apply prefixes such as frost and ice, producing frost flowers and ice flowers. 

However, the names Frost Flower and Ice Flower have been applied to two distinctly different types of ice formations leading to confusion and erroneous explanations. 

On one web page an author confesses ignorance about the winter phenomenon of 'frost flowers' and sets out to explain the phenomenon.  Without permission the author used two of my photos showing ice on plant stems and my explanation for their formation to explain a different type of ice shown in five photos from somewhere.  Those five photos show growths of ice on a frozen lake surface, supposedly in Finland.  The author does not tell us who owns those photos, nor do we know who the author of this page is.  But, my explanation does not apply to the frozen lake images shown. 

Below are two images taken from that web site.  The image on the left shows my photo of ice growing on plant stems and the image on the right shows someone's photo of ice crystals on the frozen lake surface. 

On the left is a growth of ice from a group of plant stems, in this case in Kentucky.  On the right are growths of ice on a frozen lake surface, supposedly in Finland.  Note how different these flowers are. 


On Frost Flowers or Ice Flowers on Plant Stems

The flowers of ice on plant stems are produced on only a few varieties of plants when the air temperature is below freezing but moisture in the stem is still liquid.  The process of ice segregation that produces this type of ice flower also produces needle ice in some soils, pebble ice on some rocks and hair ice on some pieces of dead wood.  In this process water moves through the stem to the ice surface, adding to the ice and pushing the ice away from the surface -- the plant stem in this case.  This type of ice is not a product of frost but it often occurs concurrently with frost in the area. 

Dr. Bruce Means was the first person in current times to publish broadly on these ice formations on plants and calls them Ice Flowers .  At least two of the plants which support such growths of ice are sometimes called frostweed and thus many call the ice formations Frost Flowers.   Many people who find such growths of ice often give them names that are descriptive of what they see.  In addition to Ice Flowers and Frost Flowers you may see names such as Ice Ribbons, Ice Fringes, Ice Filliments, Rabbit Ice, Ice Castles, Frost Castles, and Ice Leaf.  Dr. Robert Harms has proposed the name Crystallfolia based on Latin roots - basically translated as Ice Leaf. 


The Ice Flower above is on a stem of Verbesina virginica and forms what I call a scoop.  The scoop from base to top is at least 5 cm in length.  On the right the focus is on the way the curtains of ice seem to emerge from the stem, forming 3 almost parallel layers or streams.  After extending out a little way the curtains of ice merge into one forming one side of the scoop. Note the stem and grass blades are still green telling us this is not an extremely cold environment.     


On Frost Flowers or Frost Crystals on Frozen Surfaces

Dr. Todd Sformo of Barrow, Alaska, observed these flowers of ice on an April day with temperatures of about -15 C (5 F).  These displays of ice are most appropriately called frost crystals because they grow by frost being deposited on ice crystals and thus adding to the growing crystals. 

The web site explains the process and notes that the form of such crystals varies with the temperature. The morphology diagram (click to zoom)  on this site shows the different forms of frost crystals as a function of temperature.  These crystals from Alaska have a dendritic form, which is characteristic of ice crystals that form at about -15 C.  That was the temperature Dr. Sformo observed in Barrow when these crystals formed.  Note dendritic implies 'tree like', which certainly applies here. 


Some Big Errors

The Internet provides access to a great amount of information but it also facilitates the dissemination of a great amount of ignorance. 

As noted above, someone showed images of frost crystals on a lake in Finland and took photos from my web page showing ice flowers on plant stems and equated the two.  The person used my explanation for ice flowers produced by ice segregation to explain frost crystals produced by an entirely different process.  Big Error . 

In winter 2013-14 The Weather Channel featured frost flowers in two series on "the strangest weather on earth".  At the start of the segment entitled Rare Frost Flowers they introduced frost flowers by showing video clips of ice growing from a plant stem in Tennessee in November.   They also included an image of Hair Ice in this sequence, which is something quite different and does not occur in Tennessee. 

For an explanation of how these frost flowers occurred they turned to an Arctic atmospheric scientist.  She was not shown the images but took on the task of researching frost flowers.  She concluded they were products of the extreme cold and demonstrated in the video how such extreme cold might produce blossoms of ice. 

I contacted the scientist who produced the explanation and introduced her to ice flowers on plant stems and Hair Ice.   She was not familiar with these and acknowledged her explanation was not appropriate to these forms of ice.  Currently, the online clip of Rare Frost Flowers on The Weather Channel does not include her explanation or any explanation as to their formation.  

But, in that same series on The Weather Channel they have a segment entitled Arctic Blooms examining frost crystals forming on an ice surface and refer to these many crystals as both Ice Flowers and Frost Flowers.  They do not offer an explanation of how they form but note that is some cases they contain large quantities of bacteria.  The flowers shown here are frost crystals similar to those captured by Dr. Todd Sformo in Alaska. 


Other Uses of Frost Flowers

The name frost flower applied to ice on plant stems by ice segregation must go back many decades because a common name for at least two plants that produce such ice is frost flower.  The frequently cited YouTube video of the growth of ice on stems of Verbesina virginica is titled Frost Flowers. 

While such ice flowers are not an accumulation of frost, these form when it is appropriate to have frost and a crystal of frost may have been involved in starting the process of ice segregation.  Note in the image above of the ice flower from Kentucky there is some frost on the green leaves.  But, I and others argue it would be best to call such growths of ice "ice flowers" and it has been proposed to call these "crystallfolia". 

Robert Krulwich of NPR produced a web page entitled Suddenly there's a meadow in the ocean with flowers everywhere  in support of his radio report about little protrusions of ice, delicate, like snowflakes. They began growing in the dry, cold air "like a meadow spreading off in all directions. Every available surface was covered with them." "   He was told they are frost flowers. 

He goes on to offer an explanation of how these form.  Note that the last photo on the page shows good examples of dendritic ice crystals. 

The Two Forms of Frost Flowers

So, be aware there are at least two different things named frost flowers.  Both can be quite attractive in their cold environments.  Based on what we know one occurs in the middle latitudes on a few varieties of plants when air temperatures fall below freezing while the soil is still above freezing.  The other form of frost flowers occur in high latitudes when it is very cold and rather calm. 

We will not be able to change the names people use for such lovely displays of ice, but we can be aware that there are different things named frost flowers. 

Good luck on finding both types, and keep warm.  


On the World of Ice in the Age of the Internet and Digital Cameras

Now that we have the Internet and digital cameras we can see things that years ago were known only to a few local persons.  Please share your images and details of ice formations in a responsible fashion.  In the process we will gain a greater knowledge of these processes. 

For other perspectives on ice see my web pages at   Feel free to contact me at   to share your photos of ice of this nature.

One of the many web pages of Dr. Jim Carter

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