A little later I noticed white puffs off to my right, as though someone
had dropped tissues. I looked closer and saw that these objects were
ribbons of ice. They were not growing out of the ground as ice wedges
do. These ribbons seemed to be hanging from
branches. The more I review this photo I suspect the ice has
slid down the twigs from the original position. The little patch of
ice on the lower twig on the left makes me think the larger glob of ice was
once located here.
The ribbon above is made up of loops seeming to hang down from the twigs. The
ribbons show parallel bands similar to tree rings. Based on what
others have said about these, I now know the ribbons are extruded from the
stems of these plants.
In the example below you can tell the size of the ribbons by
comparing them to the Oak leaves on the ground. I originally thought
this ribbon of ice radiated out from the node at the junction of the stems.
I now realize it was extruded from the stem with more ice being extruded at the
bottom than at the top. Thus, it appears to have rotated around the
junction of the stems. This
same process seems to have occurred in the second ribbon at the bottom. I
am not ready to explain what produced the tight spiral in between these two
Below is one that seems to be curled up along one edge.
That edge does not appear to have broken off, but perhaps it was broken and
differential melting has produced this scalloping.
We broke off a piece and looked through it. These
ribbons of ice are very thin, as shown by the piece in Greg's hand. In
this example the parallel bands look like growth rings, but it likely these
striations are formed by variations in the width of the slit from which the
ice was extruded.
Below is another example, in this case above a non-leafy
surface. This demonstrates leaves are not a required component of this
process, but the stems are present.
As I remember all of these ice ribbons were found along a
north-facing slope. In December 2004 I returned to the
Park to see if I could find the place where I saw these ice ribbons the year
before. I did not find that place but I did find some ice ribbons or
ice flowers in another place and in somewhat different forms. There
are two pages
showing what I found in 2004.
In 2005 I found such ice formations
in northern Kentucky
and in central Virginia.
Check these out, for they are somewhat different than what I show here but
they are the same things.
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 got a hit on a
reprint of a four-paragraph article published in 1933 by
D. S. Libbey in Nature
Notes from Crater Lake National Park. 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
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.
White crownbeard is sometimes known as frostweed.
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,
This online article by Means does not include a photo but the 2-page
article in Natural History does contain one large photo. Means
shows nine photos
on his web page, and references to his articles about these formations. Means had a brief
article on ice flowers in the November 2004 issue of National Geographic.
The story of Means trying to find these ice flowers was the subject of an
article in the Tallahassee Democrat by Sharon Rauch.
is online and makes for interesting reading.
Means stated that these ice ribbons do not last through the
day but on shaded, north-facing slopes I could believe they might last a few
days. The size of the icicles hanging off the ends of the logs tells
me that the previous night was not the first night with freezing
temperatures. On the other hand, I am more certain that the ice in the first
photo has slid down the stem and the ice was melting when I took the photo.
Swihart in Missouri Conservation Online, writes about Frost Flowers.
She distinguishes 'frost flowers' from 'ice flowers' which she says are
created by water condensing and freezing quite quickly. Based on my
think that in the ice flower situation she describes water vapor condenses as frost on such
things as manhole covers, not as water which then freezes. But still,
she uses the term ice flower for something different from what we are
talking about here.
Swihart gives very clear descriptions of how
frost flowers form on stems and notes the same two species mentioned by Means.
Anyone interested in this subject should read her description of how these
form. She notes that
they can form on the same flower in successive freezes. Shihart's
original article was published in Missouri Conservationist, October 2000.
naturealmanac site has a page showing four examples of ice flowers sent
in by others. They lost the name of the person capturing the first
image, but Steve Haskins owns the other three photos. The flowers in
those photos are most similar to the flowers I found. Steve is from Ohio
and supposedly found his examples in Ohio. Naturealmanac also has an article about the plant Wild Oregano, noting:
Oregano (Cunila origanoides) . . . Found on dry, rocky woodland slopes
this foot-high member of the mint family has sprays of tiny lavender
flowers and is one of the last woodland plants to bloom. . . has another
claim to uniqueness since it's the only plant in our flora to
consistently produce "frost flowers". Frost flowers result when
freezing temperatures cause the sap to freeze and then while expanding
extrude through ruptures in the stem creating long ribbons of ice.
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 and he notes that
these occur in several species of plants, as:
Several species of plants produce frost flowers. The plants that produce
them on our place are white crownbeards (Verbesina virginica). These
plants have large leaves and can be taller than 6 feet. They are capped
by a rounded cluster of small, white flowers. They are also known as
tickweed, frostweed and ice-plant.
Mims goes on to discuss how these must form and gets into
various terminology relating to frost. I agree with Mims that these
are not frost, which comes about as water vapor is deposited on to a surface
in crystals of ice. I have gone through many ideas of how these
creations are formed. I thought there must be a ice in a somewhat
plastic state that is extruded through the thin cracks in the plant stem.
I tried to simulate this by freezing water in many containers with slits and
scars. It was stimulating to try many different ideas but it did
nothing to explain how these ribbons of ice form.
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. At about the same time I received an
email from Dr. Ken Orvis at the University of Tennessee, Knoxville, offering
an explanation. They note that as ice forms crystals inside the stem
of the plant water moves towards the ice crystals and passes through the
stem. As the water emerges into the air that is below freezing the water
freezes into ice crystals on the outside of the plant. As more water
emerges it freezes and pushes the existing crystal further out.
I need to spend more time in the literature but I understand
the basic process. The presence of the striations in these ribbons of
ice tell us that different size of droplets and ice crystals grown under
I keep finding sites on the to photos of these ice
Watersheds.org site of the southern Missouri Ozarks has four very
attractive photos and a discussion of how the ice forms. Sorry to say
this discussion does not provide answers to all of the questions I pose
In a lengthy Cloudland Journal for November 2003, Tim Ernst
shares observations about his Arkansas environment. In his entry for
11/24/03 he talks about going out on a cold morning to find these frost
flowers in his garden where he often finds them on ". . . the first really
good cold snap of the season." He notes "I can always count on this
spot for the best frost flowers" but they were not here this day. On
11/25 the flowers appeared and the author
photos of those frost flowers. There are some beautiful images
here. The author notes that within about 100 yards there were more
than 150 frost flowers. Interestingly, he observed that it was not as
cold this day as it was the day before. The author contributes to the
discussion of how these form when he wrote:
||Here is some info about
frost flowers (stolen from Don Kurz's OZARK WILDFLOWERS guidebook on
page 74 - the best wildflower book available ANYWHERE!).
The plant that the flowers form on is called "White crownbeard," or "Frostweed."
From Don's book: "These are ribbons of ice oozing out of cracks at the
base of the stem. Sap from still-active roots freezes as it emerges from
the dead stem, growing like a white ribbon as more fluid is pumped out."
Oh, I found a good web site for what someone calls ice flowers but these are
photos of the work of Jack Frost on
windows. The images are beautiful but they are very different from the
ice ribbons or frosts flowers shown above.
NASA has a
web page discussing and defining Frost Flowers, which are true
formations of frost. They have an attractive image of what they call
How nice it is that there are beautiful flowers to be seen
when the temperature drops below freezing, whether in the woods or on the
window. We do not have to wait until spring to see flowers--look
And what are these things called? There is no
standardization of terms. While one person calls these ice flowers,
another person uses that same term to apply to something different. I
prefer ice ribbons, based on their form. But, I appear to be in the minority.
Please send any thoughts and comments to me--Dr. Jim Carter