Ice Formations Growing From Plant Stems

Dr. James R. Carter, Professor Emeritus

Geography-Geology Department

Illinois State University, Normal IL 61790-4400


My first encounter with the growth of ice took place at Big Ridge State Park in Tennessee, USA, on a sunny day in December 2003.  The night before had been below freezing.  I saw some icicles and then I found this complex of plant stems with a cluster of ice at the base.  At the time I did not know what I was looking at but now know the plant is Dittany Cunila origanoides .  The ice is called ice flowers or ice ribbons or many other local names.   

In fall 2004 I turned to the Web to see if I could find any pages telling about such things.  I searched on 'ice ribbons' and found a reprint of a four-paragraph article published in 1933 by D. S. Libbey in Nature Notes from Crater Lake National Park in Oregon, USA.  Libbey wrote:

  "Ice ribbons are prone to occur in the chill of early winter when the ground is neither frozen nor covered with snow. The Cunila - Cunila origanoides - found up and down the Appalachian highland system is the favorite plant on which the ribbons form. Frequently similar ice ribbons have been observed growing from the stems of dead plants and weeds on the frosty slopes of the "hill" of our central plateaus."  Libbey, 1933 reprinted  

A web search on 'ice blossoms' turned up a web summary of an article by D. Bruce Means in Natural History, February 2004.  Means clearly describes what we encountered on our hike and notes that they are quite infrequent.  It took a few years before he had his second sighting of these beauties of nature in a forested area in north Florida.  He refers to these as ice blossoms in his title and as ice flowers in the article and notes that others have called them frost flowers.  He names the species of perennials on which these are known to occur--white crownbeard, yellow ironweed, and Helianthemum canadense

  "On close inspection, I saw that the "petals" of my ice flowers push their way through the vascular bundles of the dead stems: Water from the roots is drawn up the stems (either as part of the plant's natural transportation system or through capillary action) and expands as it freezes, breaking the stem walls and creating a flow of ice. The leading edge of the ice freezes to the stem's papery bark, and as the ice grows it is lifted upward by the attached bark, forming delicately curved, lacy ribbons."  Means, 2004  

Means shows nine photos on his web page, and references his many articles about these formations.   Betty Swihart had an informative article about Frost Flowers published in Missouri Conservationist, October 2000.  That article was important to me in learning about these ice formations but the article is no longer on the Internet.  She noted the ice can form on the same flower in successive freezes.  She called this type of ice formation Frost Flowers.  We know this is not a product of frost but frost is often present at the same time so we can appreciate how that name came into being. 

I posted my web page for the world to see.  A number of persons saw my pages and sent me email.  I have corresponded with many persons and I have learned in the process.  I call these ice ribbons and ice flowers based on their appearance but the term frost flowers is commonly used while there is the occasional use of ice fringes, ice filaments, and rabbit ice.  There is no established name and no authority to set a standard.  Recently, Dr. Bob Harms created the name crystallofolia which brings the crystals of ice together with flowers. 

I employed bibliographic search tools to find out about frost flowers, ice flowers and ice ribbons.  I found a few popular articles describing these unusual items, but could find no authoritative papers explaining these ice formations.  I found two plant species associated with the name frost flower:  Dittany, or Wild Oregano, Cunila origanoides, and White Crownbeard, or Frostweed, Verbesina virginicaThus, I concluded this was a concern for botany.  I showed what I had found to many colleagues in the biological sciences and only one had personally seen these frost flowers and he thought they occurred on only Cunila origanoides.  I realized this is not a botanical question. 

Dr. Forrest Mims III has an online article on Frost Flowers as seen in south Texas.  His presentation shows a good photo of one of these near the ground.  He notes they are also called frost castles or ice castles.  If you click on the photo on his web page you can see the frost that has been deposited on grass and stems nearby.  Mims has continued to pursue this topic and recently posted a time-lapse video presentation of the formation and decay of his Frost Flower. 

In November 2005 I found a good collection of Ice Flowers and Ribbons in Kentucky.  The photos above show a representative sample.  Note the frost on the green leaf in the middle photo, illustrating the link between the ice growing from the plant stems and the presence of frost.  But, do not think of these as formed by the deposition of frost. 

Then there was an article in Weatherwise (Jan/Feb 2005) about the formation of ice spikes in ice cube trays.  To explain this phenomenon they turned to Dr. Charles Knight at the University Center for Atmosphere Research.  So, I contact Dr. Knight for his perspective on the formation of these objects.  As descibed on my master page, water in the stem becomes super cooled, meaning the temperature is below freezing but that ice has not yet started to form.  If and when an ice crystal, perhaps from the formation of frost, forms on the stem the super cooled water penetrates the stem and forms as ice on the ice crystal.  So the ice crystals on the stem continue to grow as super cooled water moves through the stem.

The openings in these stems are too small for an ice crystal to pass through but are large enough for water to pass through.  As long as the water inside the stem remains liquid the ribbons of ice can continue to grow.  But, if for some reason the super cooled water in the stem turns to ice the plant stem will be ruptured.  A number of authors mention ruptured stems. 

Least you get the impression that all of these ice formations on plant stems are cute little ribbons and flowers, the images below give another perspective.  The three photos on the left show the same stem in my yard over two days.  At this height, the stem is about 1 cm or 0.4 inch wide.  The left-most photo taken at 10AM shows ice pushing the bark away from the core.  By 4PM the ice had melted and there was now a gap between the bark and the stem core.  Two days later a large growth of ice has pushed the bark far away from the core.  Further down the stem was a large display of ice on this day. 

The big barrel-like display of ice on the right, was captured by Tom Jessup in Arkansas, USA.  Based on the size of the leaves and grass stems in this photo, I estimate this is at least 30 cm or 12 inches tall.  This is the largest ice formation I have seen.  I suspect it formed on two or more stems of White Crownbeard Verbesina virginica.  When I view this large ice formation I can understand why people use the name Rabbit Ice for this type of ice.

In fall 2005 I made the link between the growth of Ice Flowers and Needle Ice.  This association gave me a new term to search on in the professional literature.  I found there is a well developed professional literature on needle ice.  In 1988 D. W. Lawler published “A Bibliography of Needle Ice” in Cold Regions Science and Technology (15: 295-310).  There are 267 items in his compilation going back to 1824.  A complementary paper is: D. W. Lawler, 1988, "Environmental Limits of Needle Ice: A Global Survey"  Arctic and Alpine Research, 20/2, pp. 137-159.

I delved into that bibliography and chased down many of the papers.  Surprisingly, many of the papers relate to these Ice Flowers and Ribbons on plant stems.  Some of these early writings are a joy to read for the choice of words. 


Stories from the 19th Century

Of particular note was the letter of Sir J. F. W. Herschel dated January 12, 1833, in Philosophical Magazine, 3rd series, 110-111, entitled: "Notice of a remarkable Deposition of Ice around the decaying Stems of Vegetables during Frost."  He wrote that years before he had found ice ". . . to incrust the stalks in a singular manner in voluminous friable masses, which looked as if they had been squeezed, while soft, through cracks in the stems."  Then on January 11 he found a similar formation of ice which he described as ". . . seemed to emanate in a kind of riband- or frill-shaped wavy excrescence, -- as if protruded in a soft state from the interior of the stem, from longitudinal fissures in its sides, . . . the structure of the ribands was fibrous, like that of the fibrous variety of gypsum, presenting a glossy silky surface"  His paper includes three sketches of these ice formations.  He goes on to make additional observations about the ice and the atmospheric conditions when these formed, all consistent with what I have observed more than a century and a half later.  He ends with "What share the physiological functions of the plant may have in the phaenomenon, or whether it be connected with the vitality of the stem at all, it is for botanists to decide." 

Herschel’s paper prompted Professor Rigaud of Oxford to recall his observation in 1821 of similar ice formations on a recently built stone wall.  “The portions of the ice (with a single exception) were formed at the edges of the stones,-- indifferently at the tops, to bottoms, or the sides, but the curvature was uniformly turned inward from the mortar itself, in which case the threads of ice were formed in an horizontal line, and I think (for of this I made no memorandum) parallel to the layer of the mortar.”  Philosophical Magazine, Feb. 2, 1833, 190-191.

In the same journal (The London, Edinburgh and Dublin Philosophical Magazine and Journal of Science, Third Series) of May 1850, 329-342, John LeConte, M.D., of the University of Georgia, USA,  wrote about many instances of observing frost flowers and needle ice in Georgia.  He quotes liberally from Hershel (1833), for he appreciated the words as I do.  LeConte also produced some lovely descriptions such as ". . . the traveler who passes along the level roads of this region soon after sunrise cannot fail to be struck with the remarkable accumulations of voluminous friable masses of semi-pellucid ice around the footstalks of the Pluchea which grow along the road-side ditches.  At a distance they present an appearance resembling locks of cotton-wool, varying from four to five inches in diameter, placed around the roots of plants; and when numerous the effect is striking and beautiful." p. 330.  He observes that in some cases ice had formed on the same plant on consecutive nights "when the wood was not rifted." p. 332.  He also makes observations about what we now call needle ice and argues "that both of the phaenomena must be referred to the same cause.  If we admit an identity of cause in the two cases, it is obvious that it must be purely physical . . ." p. 336.

Lester F. Ward, “Frost freaks of the dittany,” The Botanical Gazette, 1893, observed these near Accotink, Virginia, USA.  He has stylized drawings of the stems and ice ribbons.  He writes that the article belongs in a botanical journal because of all of the plants in the area the ice formations occurred only on Cunila Mariana, dittany.  He and a colleague tasted the ice and inferred from this that the water was not “. . . distinguishable from pure distilled water . . .” p. 185  Ward said he was able to find no records of others observing this phenomenon.  He also wrote: “It is possible that this is the first time that Cunila Mariana has been discovered to be a frost-weed.  At the time the discovery was made it had quite escaped my memory that Helianthemum Canadense behaves in a similar way.” P. 185. 

Ward references Gray’s Manual, 1848, as describing such ice formations on Helianthemum Canadense, or frostweed.  As similar statement appears in the Eighth Edition of Gray’s Manual of Botany, 1970, on p. 1017 and notes that Helianthemum Bicknellii is also called frostweed

Ward also refers to the book Sharp Eyes by Wm. Hamilton Gibson, dated 1892.  I got to see the 1904 edition of this delightfully illustrated work, where Gibson writes about what can be seen in nature every week during the year.  The November 3d entry is The Frost-Flower as it appears on Helianthemum CanadenseHe notes it has three distinct types of blossoms during the year.  In November “the flower from which the plant is named, but which few people ever see.  Almost any morning during the past week, after a severe frost, would have shown it to us among the stubble where the plants are know to grow, glistening like specks of white quartz down among the blown herbage close to the base of the stem.  It is a flower of ice crystal of purest white which shoots from the stem, bursting the bark asunder, and fashioned into all sorts of whimsical feathery curls and flanges and ridges.  It is often quite small, but sometimes attains three inches in height and an inch or more in width.  It is said to be a crystallization of the sap of the plant, but the size of the crystal is often out of all proportion to the possible amount of sap within the stem, and suggests the possibility that the stem may draw extra moisture from the soil for this special occasion.  The frost-flower is well named.”  The sketch accompanying this text shows an blossom of ice in one image overlaid on top of the plant in full bloom in summer. 

And in the Early 20th Century

Prof. Cleveland Abbe, “Ice Columns in Gravelly Soil,” Monthly Weather Review, 1905, 157-8, writes about needle ice and references LeConte, 1850.  He notes that “Only once have I seen the corresponding phenomenon of a thin ice sheet of parallel ice columns exuding from a vertical crevice in the bark of a tree, many beautiful examples of which are given by Professor LeConte and Sir John Herschel.”  Abbe rejects the explanation of LeConte and offers his own suppositions.  He calls for someone to repeat the process in the physical laboratory.  There is a concluding remark “This explanation of the growth of hollow columns of ice in gravelly soil applies with slight changes to the hollow stems and plates of snow crystals.  The whole subject of the growth of crystalline forms needs elucidation.” p. 158. 

Then I found Coblentz, “The Exudation of Ice from Stems of Plants” in the Journal of the Franklin Institute, 589-621, Nov 1914.  Coblentz was a physicist working for the National Bureau of Standards in Washington, DC.  In 1913 he found some frost flowers in Rock Creek Park and started observing what he saw.  He systematically made observations, took notes and carried out many experiments with the help of colleagues.  He found that in the mix of plants in the rocky slopes, the ice flowers occurred only on Cunila mariana, or Dittany.  He cut off stems and inserted them in moist soil, test tubes and crucibles.  He reported on how rapidly water moved up the dry stems of Dittany and was able to grow ice ribbons, what he also called ice fringes and ice filaments.  He showed that the roots of the plant are not necessary for the formation of ice, nor is the outer bark. He applied different treatments to the stems and showed that the water for the ice comes from within the stem and is not deposited from the air.  Coblentz has many photos of the ribbons he grew, as well as sketches of the setup of his experiments and of some of the ice ribbons he grew.  With this paper Coblentz demonstrates the ice ribbons are a product of a physical process.  This is an important paper to understand the nature of these ice formations because still today persons attribute the ice to frozen sap.

As discussed under ice growing from dead wood, Schwalbe (1884) demonstrated his ability to grow ice at will on pieces of wood.  Dr.  Bruce Means, The American Gardener, Jan/Feb 2005, 36, notes he transplanted the thick, fleshy-fibrous roots of flat-seed sunflowers in his home garden and in buckets of water and grew beautiful ice flowers in both experiments.  Coblentz, Schalbe and Means are the only people I know about who have grown ice under controlled conditions. 

The Plants on Which Ice Forms

We know ice does not grow from all plant stems.  On my master page of Diurnal Freeze/Thaw I show examples of such ice from the stems of White Crownbeard, Dittany, as well as ornamental garden plants Salvia and Vinca. 

These are the plants on which Ice Flowers or Ice Ribbons are known to grow.  In a few cases a number of persons recognize that these produce ice during daily freeze/thaw cycles.   I give the name of the person who identified the plant if only one person told me about this.   I am not a master of plant classification terminology and so I may have a few mistakes.  I have tried to find common names for these plants by looking on the Internet. 


Some rather common plants are listed here, such as common nettle and a roadside thistle.  These were reported by a person in Switzerland and I have never heard that these plants produced ice flowers, although such plants are common where I live.  But, maybe I have not looked hard enough to find the growth of ice on many of these plants.  Let me know if you find ice growing from the stems of these types of plants. 

  • Dittany or Stone Mint,  Cunila origanoides – widely recognized
  • White Crownbeard or Frostweed, Verbesina virginica – widely recognized
  • Yellow Ironweed or Wingstem,  Verbesina alternifolia – widely recognized
  • Frostwort, Frostweed, or Rockrose,  Helianthemum bicknellii and Helianthemum canadense – widely recognized
  • New York Ironweed,  Vernonia noveboracensis – from Jan Donaldson of middleTennessee.
  • Buttonweed,  Diodea virginiana – from Dr. Bruce Means of north Florida
  • Marsh Fleabane or sweetscent,  Pluchea odoratafrom Dr. Bob Harms of Texas
  • Firebush,  Hamelia patens  -- from Dr. Bob Harms of Texas
  • Fleabane,  Pluchea  camphorate  from some old references
  • Plumbago,  Plumbago auriculata – from Chuck Hubbuch of north Florida
  • Lantana New Gold,  Lantana x hybrida'New Gold' – from Chuck Hubbuch of north Florida
  • Trailing Lantana, Weeping Lantana,  Lantana montevidensis from Chuck Hubbuch of north Florida
  • Lantana,  Lantana camara -- from Jan MacDougal of South Carolina
  • Pentas, Star Flower, Star Cluster,  Pentas lanceolata -- from Jan MacDougal of the low country of South Carolina
  • Scarlet Sage, Texas Sage or Salvia,  Salvia coccinea – from Jan MacDougal of South Carolina
  • Scrambling Sky Flower,  Thunbergia battiscombei   -- from Jan MacDougal of South Carolina
  • Black Eyed Susan,  Thunbergia alata  -- from Jan MacDougal of South Carolina
  • Red Flowerd Manettia,  Manettia coccinea  -- from Jan MacDougal of South Carolina
  • Madagascar Periwinkle, Rose Periwinkle or Vinca Coral -- Catharanthus roseus -- from Jan MacDougal and my own observation
  • Victoria Blue Salvia,  Salvia Farinacea – from my own yard in Illinois
  • Chinese Plumbago or Willmott Blue Leadwort,  Ceratostigma willmottianum  from Sally Twyman of southwestern England
  • Corsican Hellebore or Corsican Rose, Helleborus argutifolius – from Sally Twyman of southwestern England
  • Germanders,  Teucrium arduini  -- from Richard Wanner in Switzerland
  • Colombine,  Aquilegia  -- from Richard Wanner in Switzerland
  • Purple Coneflower,  Echinacea  -- from Richard Wanner in Switzerland
  • Hemp-agrimony,  Eupatorium cannabinum  -- from Richard Wanner in Switzerland
  • Meadowsweet,  Filipendula ulmaria  -- from Richard Wanner in Switzerland
  • St. John's Wort,  Hypericum perforatum  -- from Richard Wanner in Switzerland
  • White Deadnettle,  Laminum album  -- from Richard Wanner in Switzerland
  • Throw-wort, Lion's Ear, and Lion's Tail,  Leonurus cardiaca  -- from Richard Wanner in Switzerland
  • Oregano,  Oreganum vulgare  -- from Richard Wanner in Switzerland
  • Bladder cherry, Chinese lantern, Japanese lantern, or Winter cherry,  Physalia alkakengi  -- from Richard Wanner in Switzerland
  • Alpine Pasque Flower,  Pulsatilla halleri  -- from Richard Wanner in Switzerland
  • Figwort,  Scrophularia nodosa  -- from Richard Wanner in Switzerland
  • Creeping Thistle,  Cirsium arvense  -- from Richard Wanner in Switzerland
  • Spear Thistle, Bull thistle, Plumed thistle, Roadside thistle,  Cirsium vulgare  -- from Richard Wanner in Switzerland
  • Stinging Nettle or common nettle,  Urtica dioica  -- from Richard Wanner in Switzerland
  • Loosestrife,  Lysimachia punctata  -- from Richard Wanner in Switzerland

Note that a few persons including myself have found ice growing from plants because when they found ice on one type of plant they started looking at all other plants.  If the atmospheric and moisture conditions are appropriate to produce ice on one plant then they are probably suitable to grow ice on all plants that support such ice in the local area.  So, keep your eyes open.  I am certain we will find other plants that support the growth of ice from the stems. 

I assumed this type of ice was unique to the U.S. for all of the reports of ice flowers and ribbons that I found in the literature came from the United States.  Recently I have received photos of such ice from southwestern England, the Netherlands and Switzerland.  Plus there is a photo of a classic ice ribbon on a stem on the cover of the Journal of Glaciology (1993, 39:132).  This photo was taken in northern India at 16,000 feet.  Then in 2008 I received a link to another photo of an ice ribbon in northern India. 

Thank goodness for the Internet and digital cameras for they let us exchange information about these attractive ice formations.  Please take on the task of looking for ice when the freeze/thaw processes are underway.  Feel free to contact me at   if you see any ice of this nature in your outings.

Return to the master page of Ice Formations with Diurnal (Daily) Freeze/Thaw Cycles .


One of the many web pages of Dr. Jim Carter

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