Portraits of Wildflowers

Perspectives on Nature Photography

Frostweed explains its name

with 39 comments

Frostweed ice; click for greater detail.

In the last two posts I gave plausible reasons for the name frostweed and then I batted each one down. Today’s picture provides an answer to a question that may have occurred to you but that remained unasked: So tell us already, why is Verbesina virginica called frostweed? The name comes from one of the strangest phenomena in botany. By the time the first good frost settles overnight on the lands where this species grows, almost all of these plants have gone to seed. Although each stalk stands there unappealingly as it dries out, that first touch of hard frost can cause it to draw underground water up into its base. Now for the bizarre part: the lower part of the stalk splits as it extrudes freezing water laterally, and that process produces thin sheets of ice that curl and fold around the broken stalk and sometimes even unscroll away from it. That’s what you see in today’s picture, which I took just yesterday morning in Great Hills Park; if you’re willing to take your eyes off the pretty ice formations, you can make out a dark section of stalk in the upper left. I’ve read accounts that say some frostweed plants go through a second round of this icy phenomenon when there’s another freeze, but I’ve never tried to verify that. [Update: I’ve verified it for myself.] What I can say from experience is that the extruded sheets of ice are so light and delicate and prone to break when handled that they remind me of phyllo pastry.

And now let me answer another question that may have entered your mind. The last two posts dangled the question of frostweed’s name, but today’s picture, which explains the common name, was taken only yesterday morning. How did I know, when I began this series two days ago, that the temperature would drop enough to trigger frostweed’s ice trick and allow me to take pictures? I didn’t. I was planning to wait until the first or second week of December, which is when Austin usually gets its first hard freeze, and then take a frostweed ice picture that I’d use in an explanatory post at that time. Or if I didn’t manage to get any photographs of the phenomenon this year, I was going to show a photograph from another year. It was just serendipity that the temperature yesterday morning in Austin had dropped close enough to freezing to make some frostweed plants put on their display.

© 2011 Steven Schwartzman

Written by Steve Schwartzman

November 29, 2011 at 5:12 AM

39 Responses

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  1. Impressive, both the photo and the story.

    Bonnie Michelle

    November 29, 2011 at 6:25 AM

  2. That is so cool – you challenge me to see if any thing like this happens to plants in this part of the world.

    Thanks for teaching me something new today.


    November 29, 2011 at 7:23 AM

    • I’m pleased to have shown you something new in the world of nature. I’ve read that there are a few plants other than frostweed that do the ice trick, so you may want to do some Internet searching to see if you find one of those plants near you.

      Steve Schwartzman

      November 29, 2011 at 9:24 AM

  3. Nature is surprising us at every turn–thanks for the story of the mysterious frostweed. Any more unusual wild things for those of us on the East Coast? Sally


    November 29, 2011 at 8:19 AM

    • At


      you can check the USDA map, which shows frostweed as far up the East Coast as Maryland, which, if you’re still in Delaware, puts you next door. It’s probably too late this year, but if you can identify some frostweed plants next summer (perhaps with help from someone in a local native plant society), you’ll be all set to go visit them when you get your first freeze next year. Not all frostweed plants react each time, so you can visit again with subsequent freezes.

      Steve Schwartzman

      November 29, 2011 at 9:37 AM

  4. This is a beautiful photo. I have always heard this called rabbit frost – in fact posted a couple of photos this morning (very poor compared to yours!) It is always a beautiful sight.
    Have a lovely day! Kathleen

    The Course of Our Seasons

    November 29, 2011 at 10:14 AM

    • Thanks, Kathleen. I found your post about rabbit frost and commented there that the term is new to me. I have a sense that English speakers have sometimes used rabbit as a way of indicating that something is small, cute, picturesque (just as we sometimes use horse to indicate the opposite). Yesterday was the earliest date I’ve seen frostweed do its ice trick, but maybe I just haven’t been observant enough. Let’s hope for a repeat performance.

      Steve Schwartzman

      November 29, 2011 at 10:38 AM

      • I have wondered why it was called rabbit frost and have heard a couple of different explanations.1) That it is about the height of rabbits and where they would chew on the stems of the grasses or 2) that after a hard freeze, it was safe to eat wild rabbits. I have seen it as early as the middle of Oct with a hard freeze in the Arkansas and Missouri Ozarks. And if it is early and there is still lots of moisture in the grasses, I have seen some as big as softballs, curling around the stem. Just beautiful!

        The Course of Our Seasons

        November 29, 2011 at 11:38 AM

      • Thanks for all that extra information, Kathleen. Both explanations are plausible, but it can be hard to track down the origin of a term like this. In any case, I’m glad you’ve gotten to enjoy your rabbit frost as early as the middle of October in the Ozarks; it’s still way too warm here then for us to see it.

        Steve Schwartzman

        November 29, 2011 at 11:56 AM

  5. Oh, my gosh! One of my absolute favorites. It seems so early – but then, we still were in the 80s down here last week, so my sense of what’s happening in the “outside world” is a little off.

    I first saw frostweed in a valley on the old Spicer Ranch land between Kerrville and Medina. I used to go to a cabin up there and camp out – no electricity or water, wood stove and such. I walked out one morning and there they were. I didn’t have a clue what had happened. It was magical. Of course, in an hour the frost was gone, but the next morning there were new splits, new ribbons. They can swirl and twist unbelievably – I’ve seen some that look like old-fashioned ribbon candy.

    I have a whole file of frostweed photos I was going to use for a blog entry. Now, I can’t remember what I was going to do with them. Something to ponder while I work today!


    November 29, 2011 at 10:20 AM

    • I’m happy to see your enthusiasm, Linda. Here in Austin we also had a high temperature in the low 80s one day last week, and even though it was near freezing in my neighborhood park yesterday morning (without which I wouldn’t have been able to post today’s picture), by afternoon we were back in the low 60s; today is likely to be even a little warmer.

      Although I’ve lived in Austin since 1976, only about five years ago, after reading about the frostweed phenomenon, did I finally make myself go out early one frigid morning in hopes of seeing it (one reason I left New York was to get away from the cold). Sounds like you beat me to the white magic in the Hill Country. Local linguist-turned-botanist Bob Harms has posted a detailed and thoroughly illustrated article about crystallofolia that may interest you and other readers.

      As for your file of photos, I hope the frostweed of your imagination will extrude them into a post in your blog.

      Steve Schwartzman

      November 29, 2011 at 10:59 AM

  6. Amazing! Nature at its best. Thank you for the explanation, I would never have guessed how that icy cocoon was formed.


    November 29, 2011 at 11:51 AM

    • It is an amazing phenomenon, isn’t it? I’m grateful to live in a place where I can see it, even if I’m not so fond of staying out in the cold to photograph it. Another price I pay for pictures.

      Steve Schwartzman

      November 29, 2011 at 12:00 PM

  7. An amazing photograph to explain this phenomenon; well framed and lit! Thanks for the explanation and the image!


    November 29, 2011 at 3:15 PM

    • You’re certainly welcome. The lighting, by the way, was natural: because the frostweed was still in shadow, that meant a high ISO, fast shutter speed, and an aperture in this case of only f/6.3, which made it hard for me to get much depth of field. As a result, only the frontmost parts of the ice are in focus. All in all, though, the picture seems to work well. On some other pictures I used my ring flash, but in general I don’t like the harsher look that comes with flash, even if I can stop the lens down then and get more depth of field.

      Steve Schwartzman

      November 29, 2011 at 4:02 PM

  8. Nature is so remarkable, isn’t it? And the serendipity of the frost coming as you were engaged in this series of photographs, well, what a gift (to all of us)!

    Susan Scheid

    November 29, 2011 at 7:07 PM

    • Yes, nature is remarkable. After 12 years I’m still discovering things. It’s been said that fortune favors the prepared, and one interpretation I’ve put on that is that if I’m out there often enough, things will come my way. That said, the frost that came to the frostweed yesterday morning was an unanticipated bonus.

      Steve Schwartzman

      November 29, 2011 at 7:37 PM

  9. This is awesome and beautiful! We don’t have Frostweed here, instead we have ugly red clay that sends up frozen ice shards. The longest of these I’ve found so far was about 3 inches in height. Strangely, there always seems to be a small stone sitting atop each spire.

    I think I’d prefer the Frostweed. ~ Lynda


    November 29, 2011 at 7:28 PM

    • Although you might prefer the frostweed, Lynda, the ice shards that you say come out of the red clay near you sound intriguing, especially if you can get in close with a macro lens.

      Steve Schwartzman

      November 29, 2011 at 7:38 PM

  10. What an incredible plant!


    November 30, 2011 at 10:24 PM

  11. […] In the posting for November 29 you learned that Verbesina virginica is called frostweed because of the thin sheets of ice that the plant extrudes through the base of its stem when the temperature falls to freezing. Eight mornings later, after the overnight temperature in Austin had dropped into the high 20s, I went back out to Great Hills Park to see how the frostweed plants there were doing. I found only a few with ice formations on the north side of Floral Park Dr., but a bunch on the south side, where I ended up spending most of my time. Because the frostweed phenomenon occurs at the base of the plant’s stem, spending my time meant kneeling, sitting, hunching over or lying down in order to be low enough to aim my camera horizontally at the mostly upright ice formations. […]

  12. Steve, I think mine are of a different plant. You will notice that the way the ice extrudes on mine is more of a vertical eruption than a horizontal, ribbon-like extrusion, as is portrayed in your two photos. Our frost flowers seem to mostly be of the type in my photo, although I can recall having seen some like in your photos… http://fromthebackforty.com/2012/02/02/frost-flower/#comment-60


    February 4, 2012 at 9:42 AM

    • I was looking for attractive formations—and appealing ways to show them off—rather than ones that are the most typical of this phenomenon. But I have seen plenty of frostweed ice formations like the one in your photograph.

      Steve Schwartzman

      February 4, 2012 at 10:23 AM

  13. […] the summer heat feels oppressive, you’re welcome to take a cooling look back at the posts of November 29 and December […]

  14. Fascinating! And as always very beautiful How serendipitous that you should receive a frost the previous night.

    Cindy Kilpatrick

    August 7, 2012 at 9:13 PM

    • Yes, the timing was serendipitous indeed. These ice formations are something to behold: I hope you’ll get the chance someday.

      Steve Schwartzman

      August 7, 2012 at 10:13 PM

  15. Extraordinary! How wonderful nature is – and diverse!


    August 8, 2012 at 7:13 AM

  16. […] If you don’t recall or don’t know what Verbesina virginica looks like when it’s fresh, you may want to take a quick look back at a picture from this summer. As for the origin of the vernacular name frostweed, let me repeat what I wrote at the end of November last year. The common name for this species comes from one of the strangest phenomena in botany. By the time the first good frost settles overnight on the lands where frostweed grows, almost all of these plants have gone to seed. Although each stalk stands there unappealingly as it dries out, that first touch of hard frost can cause it to draw underground water up into its base. Now for the strange trick: the lower part of the stalk splits open as it extrudes freezing water laterally, and that process produces thin sheets of ice that curl and fold around the broken stalk and sometimes even unscroll away from it (you can see that unscrolling in a photograph from last year). […]

  17. I’ve looked at all your frostweed photos, such a fascinating plant—I’ve never so much as heard of it before, whether the exuberant white or the simple yellow. The white looks to be very fragrant. Do bees also enjoy it? Speaking of frost and flowers: now that this wild winter we’ve been having is finally edging reluctantly but ineluctably into spring, may I share with you, in words, in winter’s honour, a stunning scene I was privileged to encounter, from inside an upstairs room, one very chilly morning in January? (I guess you’d have to say that, having beheld, I feel myself beholden to share, as best I can!) I’ve seen plenty of frosty window art in my time, but never a piece like this . . . Imagine a meadow within a tropical rainforest, myriad species of grasses, flowers, ferns and fronds arcing, feathering, sweeping, growing thickly yet not in an embattled tangle where none is easily recognizable, but perfectly and beautifully ‘arranged’ as though by the brush of a wild genius painter . . . dream art it was, a gift for a lifetime. (Probably you could have captured these wildwinter wildflowers well in a photo, but sadly I would never have begun to do them justice had I even tried—which I didn’t because my camera seems to be broken.)


    March 7, 2014 at 2:12 PM

    • The white-flowering frostweed, the one we have here and the only one I’m familiar with, has a scent, but nothing I’d rave about. Insects, though, definitely seem attracted, and I’ve seen little visitors of many kinds (including bees) on the flowers.

      Thanks for telling about the frosty vision you were granted, one consolation of the harsh winter that so many people have suffered through this year. I’m sorry your camera was broken, though, because a picture would have been a great memento, judging from your lush description, even if it didn’t do full justice to what you experienced. When I was a kid growing up in the suburbs of New York we used to get pretty frost patterns on our windows every winter, but here in Austin, even on those rare occasions when the weather is cold enough, nothing ever happens on our windows.

      Steve Schwartzman

      March 7, 2014 at 3:09 PM

  18. […] 2011 […]

  19. […] you’re unfamiliar with this strange phenomenon, you can go back to a post from 2011 that explained […]

  20. […] me make up for not showing you any flowers of that species this past fall. If you didn’t know the real reason that frostweed is called frostweed you might think it’s because of these white flowers. This tall plant (up to 3m, or 10 ft.) is […]

  21. Fascinating!


    January 2, 2018 at 10:00 PM

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