My World of Ice
Dr. James R. Carter, Professor
Illinois State University, Normal IL
Living in Midlothian, Virginia, USA
2003 I saw my first ice growing on plant stems. Since then, I have been
introduced to ice in many different forms.
For the big overview
with many photos and links to a diversity of pages.
In 2013 I wrote an integrated series
of 5 web pages examining the products of Ice Segregation in
Flowers on plant stems; Needle
Ice in the soil; Pebble
Ice on small rocks at the surface; Hair
Ice on dead wood. These pages with many photos are kept up to
In fall 2013 The
American Scientist published my article entitled
"Flowers and Ribbons of Ice". A photo of one of my Ice Flowers
graced the cover of the journal. The article was revised slightly,
translated into French and reprinted as "Les fleurs et les rubans de glace" in Pour la Science. Then it was revised slightly, translated
into German and reprinted as "Blüten und Bänder aus Eis" in Spektrum der Wissenschaft. In fall 2014 Investigacion y Ciencia
reprinted the paper as "La belleza de las flores de hielo" in
In 2020 I presented my story for
Lunchbreak Science at the Science Museum of Virginia. It was recorded and
put on YouTube under the title “Breathtaking
Ice Formations: Discovering Frost Flowers, Needle Ice and Other Natural
In 2021 “The Surface Expression of Ice
Segregation: Needle Ice, Pebble Ice, Ice Flowers, and Hair Ice” was
published in the Journal of Geography and Earth Sciences, Vol. 1,
No. 9, pp 1-16. A copy of the paper can be downloaded from this site as a
Ice Flowers are often called Frost
Flowers. I found the name Frost Flower is also applied to an entirely
different form of ice, leading to confusion. I have tried to clarify
In 2009 I put together a web page
with many links showing how much of these forms of ice relate to the diurnal
(daily) cycle of warming and cooling. The page with many photos
integrates most of my experiences up to that time but I have learned a lot
Early in the process, I found a
bibliography from Lawler, 1988, citing 267 writings going back to
1824. I have tried to summarize some
of the more relevant observations and studies from the past.
an update of my original web page with many links. I am keeping this page because others may
be comfortable with it and on occasion turn to it to find an item or a
I found my
first ice in east
Tennessee in December 2003 on Dittany, Cunila
December 2004 I found Ice
Flowers in east Tennessee on Verbesina
virginica, White Crownbeard
2005 I found Ice Flowers on Verbesina
virginica in northern
late I found a small ice flower on a Boneset-type plant I have yet to
identify next to Needle Ice and a rod of ice I now identify as Pebble Ice.
This find was about 30 miles
west of Richmond, Virginia.
I was not
able to find any Ice in 2006, but it was not for trying. I was looking. But
I found seeds of Verbesinas and planted
them in my yard.
2007 I had ice on plants on more than 20 days in my own yard.
I had many
different ice formations in
fall 2008 and took many photos.
pages on Ice attracted emails of persons who found ice in many different
configurations. So, I got some interesting inquiries. In January 2007 I
explored extruding ice from
pipes. And, in winter
2007-08 I had even more success in extruding ice from
ice on branches of wood, more common in Europe than in N. America. I
now know such ice on wood is called Hair Ice, but it was strange to me when
I was sent my first photo in 2006.
In the Jan/Feb 2009 issue of Weatherwise I have
an article entitled: Unusual Ice Formations: Studying the Natural Growths
of Ice from Soils, Stems, Branches and Rocks, pp. 34-40. This article
brought together for the first time the products of Ice Segregation at the
Earth’s surface, being Ice Flowers, Needle Ice, Pebble Ice and Hair Ice.
My Story of How I Came to Understand Such
2004 I posted my web page for the world to see. A few of persons saw
my pages and sent me email. I have corresponded with a number of
these persons, and I have learned in the process. I called these
ice ribbons and ice flowers based on their appearance but because the term
‘frost flowers’ is commonly used for another form of ice, I prefer ‘Ice Flowers’.
Because these forms of ice may be whimsical in appearance, they may be
given any name, including ice fringes, ice filaments, and rabbit
bibliographic search tools to find out about frost flowers. 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 virginica. Thus, 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.
He said he was sorry he never took this on as a research topic.
Ice Flowers and Needle Ice
in Alabama sent photos, three showing ice
flowers and one showing needle ice. He suggested they were related, but I
rejected that association because I was convinced it was a botanical
issue. Then in Virginia in 2005 I
found ice flowers and needle ice in the same immediate area, as shown
above. By golly, he was right.
back to other correspondence and found another statement relating ice
flowers and needle ice. I then turned to bibliographic search tools
and 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. I delved into many
of the papers cited there.
Stories from the 19th Century
Of particular note was the letter of 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" 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."
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 a
horizontal line, and I think (for of this I made no memorandum) parallel to
the layer of the mortar.” Philosophical Magazine, Feb. 2,
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 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.
the Duke of Argyll writing in the January 22 issue of Nature
described such ice formations and asked for a scientific explanation of
this phenomenon. In the January 29 issue three persons weighed in
with opinions based on what they had seen. In the February 19 issue
the Duke of Argyll responded. In the February 26 issue one of the
earlier writers and a new writer offer their suggestions based on ice
formations they have seen. All of these
contributors were from what we now call Great Britain. In the April
22 issue Wm. LeRoy Broun from Vanderbilt
University describes the growth of
needle ice and compares it to the ice formations observed in Europe.
Broun does not reference LeConte who was also
from the southeastern U.S.
on the meeting of the Physical Society in Berlin, in the March 13, 1884,
issue of Nature includes a discussion from Prof. Schwalbe on flowers
growing from rotten twigs lying on the ground as ". . .
ice-excrescences of soft, brilliant, asbestine appearance, and uncommonly
delicate to the touch. . . ." Prof.
Schwalbe brought some of these withered and rotten twigs with him to Berlin,
and it was in his power to produce on them at any time the phenomenon just
described. For this purpose all that was
needed was thoroughly to moisten the twig, in such a manner, however, that
no water dropped off, and then to let it cool slowly in a cold
preparation. Ice-excrescences also appeared of themselves on twigs
lying in the garden whenever the temperature fell below 0
degree C. in the night." (p. 472) He made
reference to the explanations of LeConte,
1850. I originally assumed these were ice flowers but subsequently I foud others reporting these phenomena on rotten
twigs. I have a separate web page on these ice formations, which
are called Hair Ice, Haareis, Kammeis,
Pipkrakes and Silk Frost.
editions of Nature, there were a series of letters reporting on ice
formations and reacting to earlier letters. Most of these reports
relate to what was obviously needle ice but, in the January 1, 1885, issue
B. Woodd Smith tells of a friend who “. . .
picked up a piece of a dead beech-branch which was covered with filamentous
ice, such as is described by the Duke of Argyll and others.” This
person found the ice reappeared again the next morning when it was left out
overnight. (p. 194).
at the observations and vocabulary of these authors, writing more than 120
years ago. Do we know more about frost flowers and needle ice than they did
back then? We certainly know more about needle ice, as evidenced by
the many articles cited in Lawler's bibliography. Among these papers are
reports of scientists growing needle ice and controlling the rate of
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.
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.
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 Canadense’. He 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 known 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
a blossom of ice in one image overlaid on top of the plant in full bloom in
And in the Early 20th Century
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.
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. He noted one ice flower weighed 5 grams and
observed that many were of this size.
Schwalbe (1884) in the Harz Mountains, Coblentz appears to be the only
person who has systematically grown ice ribbons and reported on them.
(Mention should be made of Bruce Means, The American Gardener,
Jan/Feb 2005, 36, who mentioned he grew beautiful ice flowers on stems of
flat-seed sunflowers.) Coblentz has many photos of the ribbons he grew, but
the copy of his paper I saw was on microfilm and the photos were not very
clear. He has sketches of the setup of his experiments and of some of
the ice ribbons he grew and thus 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 today many web sites
attribute the ice to frozen sap.
The Environments in Which Such Ice
Formations Are Found
process works only on the stems of particular plants.
Coblentz carried out his observations on Dittany, Cunila
mariana, which is now known as Cunila origanoides.
Many persons have observed that Frostweed (Verbesina
virginica) or White Crownbeard, produces such
ice ribbons. And others write about Frostweed (Helianthemum
canadense) and note it produces these ice formations. I have seen
many examples of ice formations on Dittany and White Crownbeard,
but I have not been able to find any photographic images of such ice on
frostweed Helianthemum canadense. But I will continue to
look. Subsequently, I have found such ice formations on other
plants , as noted elsewhere.
LeConte (1850) wrote “The
plants on which I have observed it are two species of the genus Pluchea of DeCandolle, or
Conyza of the older botanists, viz. Pluchea
bifrons and P. camphorate.” I
have not been able to relate these species names to ice formations nor have
I been able to find new species names that were formerly known by these
names. I assume LeConte observed his ice
formations on one of the three species we know about today.
stated that he first saw such ice “. . . round the roots and stumps of some
dry and decaying thistles.” The second time he found such ice on
stumps of a bed of heliotropes, but these stumps included stems as he
describes in his paper. I cannot tell what specific plants were
involved in the formation of these ice formations.
A. Hillefors wrote about “Needle Ice on Dead and Rotten
Branches” in Weather, 1976 (31, pp. 163-168). He observed
these in Sweden. The photos I saw were on a poor-quality photocopy.
Then, in early 2006 I received an email and three photos from Wales showing
flowers of ice growing from rotten branches. In these photos the ice
appears to be a little more needle, like but it is quite attractive.
Subsequently, I have received photos of such ice on pieces of rotten wood
on the ground from a number of places in Europe
and from the Pacific northwest and eastern Canada. These ice
formations are not the same as Ice Flowers on stems extending up from the
ground. But they occur under similar weather conditions. These
have been called Haareis, Kammeis,
Pipkrakes and Silk Frost. I am certain
these are the same ice formations Schwalbe wrote about in 1884. We now know this is Hair Ice.
while the ice formations based on dead and rotting wood are mostly from
Europe and the Pacific NW of America and the ice flowers based on the
stems of plants are mostly in the eastern part of the USA, 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. So, I must be
careful when making generalizations about what
occurs where in our big world.
December 2006 I received an email from The Weather Doctor Kieth Heidorn who
referenced his web page where he has two photos of long and thin ice
ribbons that formed on a metal fence rail. The photos came from
Sheryl Terris of Vancouver
Island, Canada. She is quoted as saying she gets these ice
formations year after year on the same gate. These appear to be consistent
with the observations of 1821 of similar ice formations on a recently built
stone wall. With her permission I put together a web page showing her great photos.
Then I experimented and was able
to extrude ice that is very similar to Sheryl's photos.
summary, we know the formation of frost flowers, ice flowers or ice ribbons
is a physical process, not related to the growth of a biological
organism. These ice formations occur on the stems of a few species of
plants and on certain pieces of rotten wood on the ground. I thought
I could count the numbers of species on which these form
and then I hear from a woman in central Tennessee
who found these on New York Ironweed Veronia
noveboracensis. She convinced me she
knew her plants and thus I added the stems of another plant on which these
occur. And, through these web pages I have heard from others and now have identified about 40
plants on which these occur. I thought they occurred only on dead
stems, but last fall I saw them form on stems that were alive.
when the water in the soil remains above freezing while the air temperature
falls below freezing. The conditions would be optimal on clear nights
with no wind, when the dominant cooling process is
net radiation. This fits the description of many reports of
observations of ice ribbons, but there are reports that these also occur
under quite windy conditions. See Tim Ernst: http://www.cloudland.net/Nov03journal/Nov03Journal.html
for the dates of 11/24/03 and 11/25/03.
Tim Ernst story has evolved. See the link to his archives at:
appears that the images I referenced in the first decade of the 20th
Century are not currently available as of 2020. After observing these many
times during the fall and winter of 2007 I know the only criteria is air
temperatures below freezing and a soil temperature above freezing.
On the Processes of the Formation of Ice
Flowers, Frost Flowers and Ice Ribbons
the process that leads to the formation of these ribbons of ice? The
stems of these plants and certain rotten pieces of wood serve as conduits
to transmit water from the soil which is above freezing to a surface which
is below freezing. (I cannot conceive how a fence rail could stay
above freezing while the air outside is well below freezing. I'm
thinking about that.)
Knight of UCAR offered an explanation in an email (2 Feb 05): “The reason
this sort of thing happens is that ice cannot grow in supercooled water
through very small openings, but water, of course, can flow through the
openings. So, one can have an ice crystal in contact with a wet
porous material, and it grows at the contact, pushing the ice crystal away
while the supercooled water flows to the contact.”
is another necessary condition for the formation of the ice -- the dew
point temperature of the air must be below freezing, and the temperature
must fall to the dew point, or more properly the frost point. When
the temperature falls to the frost point, ice will start to form on
surfaces. The crystallization of the ice should be sufficient to
start the growth of ice flowers or Haareis, etc.
pointed me to the paper by Ozawa and Kinosite,
“Segregated Ice Growth on a Microporous Filter” Journal of Colloid and
Interface Science, (132: 1, 1989). They define ice segregation as
“. . . the phenomenon in which, through freezing, ice grows out from
moisture-containing porous material such as soil.” (p. 113). They
conducted experiments growing ice over many hours while making very
detailed measurements. They found the water to be supercooled and
colder than the surface where the ice forms. But, in their experiments they
started the freezing process by introducing a droplet of ice on the surface
of the porous filter. They show that the latent heat of fusion flows
from the surface of freezing to the supercooled water. They conclude
their paper by considering these processes in soils and the formation of
needle ice and/or ice wedges. They do not seem to be aware of ice
ribbons or frost flowers.
what we observe when we see ice flowers or frost flowers is ice segregation
along the stem of a plant. When the supercooled water penetrating
through the stem encounters the first crystals of frost the supercooled
water turns to ice. That process continues and new ice is added at the
stem-ice boundary. This pushes the old ice out and away from the
stem. If the stem is not ruptured over the night, the process can go
on continuously until the ambient air temperature rises above freezing or
there is a limit to the supply of water in the plant stem and soil.
observed that such ice flowers will reoccur on subsequent nights showing
that the water in the stems does not always freeze. And it is known
that such ice formations may occur in the same area over many nights in
late fall and winter.
In fall 2007 I observed the
rates at which such ice forms on stems of White crownbeard
in my own yard. I show this by a sequence of three photos over one
night. Forrest Mims III has a better record with a time-lapse video on his
to the wide reach of the Internet, we are learning more day by day.
If you have observed the growth of these ice flowers, ribbons or whatever
you call them and can add insight into the process, please let me know.