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The frostweed, yes.

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I don’t know if Carl Sandburg knew about frostweed’s magic ice trick, but those of you who’ve been coming here for a while sure do. When the Austin temperature dropped to 26°F (–3°C) on New Year’s Eve, I knew there was a strong likelihood for frostweed ice on January 1st. When morning came, I dressed warmly and headed for a stand of Verbesina virginica I know in Great Hills Park, there to spend two hours in the cold taking scads of pictures.

If you’re not familiar with the frostweed ice phenomenon, you can read more about it in an early post.

© 2018 Steven Schwartzman

Written by Steve Schwartzman

January 2, 2018 at 4:33 AM

Frost, but not from frostweed

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The weather forecast for the early morning of November 20th in Austin predicted a temperature of around 37°, which has occasionally been cold enough to cause frostweed to do its ice trick. Living up to the nature photographer’s creed, I dressed warmly that Sunday morning, put on my rubber boots, and wended my way the half-mile downhill to check out the stand of frostweed I rely on in Great Hills Park. No luck.

While I didn’t find frostweed ice, I did find some frost, most noticeably on a colony of straggler daisies, Calyptocarpus vialis. Straggling, which is to say being low and little, works to the advantage of this species: none of the other plants that might have made for even better frost subjects survived the frequent and relentless onslaught that the mowers carried on at the Floral Park entrance to Great Hills Park all through 2016.

(I’ll occasionally interrupt pictures from the Southwest trip with a current post about central Texas.)

© 2016 Steven Schwartzman

Written by Steve Schwartzman

November 22, 2016 at 4:52 AM

Ice and flowers minutes apart

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Goldeneye Flower Head by Flameleaf Sumac 2512

After I spent 75 minutes on January 5th taking pictures of frostweed ice in Great Hills Park, I went a few blocks away to Morado Circle and photographed some of the flower heads on a goldeneye bush, Viguiera dentata. The overnight dip below freezing didn’t seem to have hurt the flowers at all, but continuing cold mornings over the next two weeks did apparently bring about the demise of almost all the flower heads, because when I checked the bush several days ago I found just two.

The leaflets behind the goldeneye flower head in this picture were from a flameleaf sumac, Rhus lanceolata, that somehow managed to hang on to its foliage into January.

© 2015 Steven Schwartzman

Written by Steve Schwartzman

January 22, 2015 at 5:30 AM

Frostweed flowers

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Frostweed Flowers 9033

You’ve recently seen a couple of pictures of frostweed ice in Great Hills Park, but I haven’t showed you any pictures of frostweed flowers in a long time. Here, then, from September 29th of last year, also in Great Hills Park, are some flower heads of Verbesina virginica, a species that is pleasingly white in two quite different ways and temperatures.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

February 25, 2014 at 6:02 AM

No frost, but frostweed did its icy trick

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Frostweed Ice 8064

Early this week we had afternoon highs in the low 80s, but then an Arctic front came through and the weather turned bleak, windy, and cold. When I looked at the outside thermometer yesterday morning and saw that the temperature was 28°, I knew I had to drive the half-mile downhill to check the place in Great Hills Park where frostweed grows in goodly numbers. Sure enough, several dozen Verbesina virginica plants had done their magic ice trick, and I found plenty to photograph in the two hours that I spent out there in the cold (oh, the sacrifices that we nature photographers make).

Those of you in northern latitudes have lots of chances to take pictures of snow and ice, things that are rare down here in Austin. Today’s photograph shows the one form of ice that we have here that most of you have never seen, except perhaps in this blog for the past two years. If you’re not familiar with what’s going on here, I’ll repeat the explanation I’ve given before. The common name for this species comes from one of the strangest phenomena in botany. By the time of the first good overnight frost (i.e. freeze), almost all of these plants have gone to seed. Although each stalk stands there dried out and unappealing, the freeze 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 out around the broken stalk.

In this latest photograph you’re looking at a pair of frostweed stalks, each with ice sheets scrolling in two directions.

© 2013 Steven Schwartzman

Written by Steve Schwartzman

December 8, 2013 at 6:00 AM

Nice ice thrice

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Click for greater clarity.

Click for greater clarity.

Last week you saw a picture of the frostweed ice I spent a couple of hours photographing on December 11. In a later post that showed a deer’s antler I mentioned a repeat performance of the ice on the morning of December 12. On those days the afternoons warmed up seasonally, and on December 18 and 19 we had record highs of at least 80°. Then, in a reversal, a cold front blew in, and on the solstice morning of December 21 my outdoor thermometer showed that the temperature had dropped close to freezing. I wondered if the frostweed could have produced a third round of ice, and when I checked the location in Great Hills Park that I’d gone to the other two times, I found that it had. Lucky me! This was the first time I’ve ever photographed frostweed ice three times in one season (even one fortnight, as the British say).

I don’t know if any of the affected plants this third time were among the ones that had produced ice on either of the other two mornings. I would’ve had to mark all the plants I saw the first time, and that amount of work would have taken me away from what I was there for, which was pictures. And speaking of that, look at how different the ice in today’s photograph is from the ice you saw last week: this time it spreads farther out and is much more irregular. Vive la différence!

© 2012 Steven Schwartzman

Written by Steve Schwartzman

December 23, 2012 at 6:17 AM

Frostweed flowers make an early appearance

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Click for greater clarity.

Since the end of last year I’ve pointed out native plants that have been flowering well before or after their “normal” time. Here’s yet another: it’s frostweed, Verbesina virginica, whose flowers don’t usually appear till September. I found these blossoms on June 19 across the street from a corner of Great Hills Park in northwestern Austin.

If you take a good look at the picture above, you may notice that a tiny dark fly was getting sustenance from these white flowers. If you don’t know or recall how frostweed got its name, especially if you’re in a place where the summer heat feels oppressive, you’re welcome to take a cooling look back at the posts of November 29 and December 9.

© 2012 Steven Schwartzman

Written by Steve Schwartzman

July 10, 2012 at 6:04 AM

Frostweed revisited

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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.

I selected today’s photograph of frostweed’s strange ice phenomenon because it differs in several ways from the last one: today’s is vertical, it shows much more of the plant’s split stalk, and—by virtue of being the last picture I took—it shows some of the sunlight that had begun falling on the ground and that meant the ice formations would soon begin to flake apart and melt.

To see the many places in the southeastern third of the United States where Verbesina virginica grows, you can consult the state-clickable map at the USDA website.

© 2011 Steven Schwartzman

Written by Steve Schwartzman

December 9, 2011 at 4:53 AM

Frostweed explains its name

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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

The change from Tuesday morning to Wednesday morning

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From Monday’s weather forecast I learned that the overnight temperature into Tuesday morning would drop a few degrees below freezing. Sure enough, when I checked the thermometer early Tuesday morning it read 29°. Equally sure enough, that meant I had to dress warmly and go out into the cold for the season’s first possible pictures of frostweed ice. I drove the half-mile to my usual stand of plants (Verbesina virginica) in Great Hills Park and found—nada. Despite the freeze, not a single frostweed plant had produced ice.

On Wednesday morning the thermometer read 32° and I gave the project a second try. This time a couple of dozen frostweed plants had woken up and remembered what they’re supposed to do when the temperature drops to freezing, and they did it, as these two photographs confirm. The second image is more abstract, which I consider a good thing in my quest for different ways to photograph a familiar subject.

If the frostweed ice phenomenon is new to you, you’re welcome to look back at previous posts to learn more.

© 2019 Steven Schwartzman

Written by Steve Schwartzman

November 14, 2019 at 4:41 AM

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