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A second round of frostweed ice this season

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After I awoke yesterday morning and saw that our outdoor thermometer showed exactly 32°F (0°C), I knew that after the sun rose I’d be heading down to Great Hills Park to find out if the frostweed plants (Verbesina virginica) had gone through a second round of their famous ice trick. The view from where I parked didn’t look promising, but once I walked down the slope to the frostweed plants, I saw that there’d be enough ice to work on. In fact I ended up spending a little over three hours there.

I took the third picture at almost 11 o’clock, when the temperature
had risen to 45° and the frostweed ice was slowly melting.

If you’re not familiar with this unusual phenomenon, what happens is that when the temperature drops to freezing the frostweed plant draws water up from underground via its roots and extrudes it through the splitting sides of its stalk as delicate sheets of ice, mostly close to the ground. You can learn a lot more about the science of frostweed ice in an article by Bob Harms.

© 2020 Steven Schwartzman

Written by Steve Schwartzman

December 18, 2020 at 4:34 AM

Frostweed ice and frostweed frost

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The overnight temperature dropped enough from November 30th into December 1st for frostweed (Verbesina virginica) to do its magic ice trick, as I found when I spent a couple of hours that morning taking pictures in the shade in Great Hills Park (the sun hadn’t risen above the trees yet). I made photographs with and without flash; the latter came out softer and bluer, as you see above. If you’re new to the frostweed ice phenomenon, you may want to read an excellent article about it by Bob Harms.

Many frostweed leaves had actual frost on them, as shown in the second picture.

© 2020 Steven Schwartzman

Written by Steve Schwartzman

December 2, 2020 at 4:33 AM

Frostweed ice abstraction

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Envious of the ice and snow pictures that some of you who dwell in the lands of true winter have been showing lately, this morning I finally got a chance to follow suit after the overnight temperature dropped to freezing and a few frostweed plants (Verbesina virginica) in Great Hills Park did their magic ice trick. Shown here is a little piece of ice that separated from the frostweed stalk it had formed on.

If the phenomenon of crystallofolia is new to you, you can find a basic explanation in a post of mine from 2012 and a thorough treatment in an article by Bob Harms.

© 2019 Steven Schwartzman

Written by Steve Schwartzman

January 24, 2019 at 11:48 AM

Frost and frostweed ice

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As yesterday gave way to today, the temperature in Austin dropped below freezing, so out I went this morning to check on a stand of frostweed (Verbesina virginica) that I rely on in Great Hills Park. Sure enough, a couple of dozen plants had done their magic ice trick. The one shown here did so right next to a straggler daisy (Calyptocarpus vialis) that conveniently harmonized with it by getting frosted in its own right. If you’d like a better view of the straggler daisy, click the thumbnail below.

And if you’re not familiar with the frostweed ice phenomenon, you’re welcome to read more about it.

© 2018 Steven Schwartzman

Written by Steve Schwartzman

November 14, 2018 at 4:18 PM

Frostweed ice: toward abstraction

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The extrusion of ice by frostweed (Verbesina virginica) is a great natural phenomenon. Austin’s temperature stayed mostly below freezing from the morning of January 1st, when I went down to Great Hills Park to take my first photographs of the new year, through this morning, when I returned for a second round of frostweed pictures, even more than two days earlier. Frostweed ice offers an opportunity for photographic abstractions, and that’s what you’re seeing here. Unlike the picture you saw last time, which involved flash, today’s images were made by natural light, which necessitated wider apertures that produced a softer feel.

© 2018 Steven Schwartzman

Written by Steve Schwartzman

January 3, 2018 at 6:00 PM

The return of frostweed ice

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Frostweed Ice 2804

On the just-below-freezing morning of January 23rd I went back down to Great Hills Park and found more frostweed plants with extruded ice near their bases than when I’d visited 12 days earlier. Of the many pictures I took on that return outing, I’ve chosen to show you two that are rather different from the two you saw last time.

For the image below, I noticed a small piece of frostweed ice broken off on the ground, so I picked it up, held it out against the sky, and photographed it. The morning was bright (as you can see from the background in the first photo), yet the camera’s sensor rendered the clear blue sky dark in comparison to the sheen of the ice. That’s a reminder of how much more sensitive to light our eyes are than the cameras we use.

Frostweed Ice Detached 2732A


How quickly the time has passed: one year ago today we began our four-week trip to New Zealand, which yielded 72 posts for this blog.

© 2016 Steven Schwartzman

Written by Steve Schwartzman

February 1, 2016 at 5:05 AM

Frostweed ice thrice

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Frostweed Ice on Two Stalks 2411

Last month you saw a picture of frostweed ice for the second time this season. That photograph was from December 29, but when we had a morning about as cold two days later, I checked the patch of Verbesina virginica plants in Great Hills Park again and found not a single bit of ice. I figured that might be it for this winter, but on the colder morning of January 5th I discovered ice emerging from more of the plants than in either of my two previous sessions. Duty-bound by the nature photographer’s oath never to pass up a chance for good pictures, I put on several layers of clothing and my hip-high waterproof boots, then went back and ended up spending 75 minutes kneeling and even lying on the cold ground. Ah yes, dedication.

The first picture of frostweed ice you saw this season was taken with a flash. The second was not, and in fact none of the photographs from that session included flash. On this third and last occasion I took every picture with my ring flash. When photographing frostweed ice I usually go for close and abstract images, and I almost always aim horizontally or even somewhat upward to avoid the clutter on the ground around the base of the stalks. It occurred to me, though, that for a change I should show you an in situ image of the phenomenon, so here it is, clutter and all. At least this picture has the virtue of including two “frost flowers,” and the ice is more horizontally expansive and ribbony than in the other pictures you’ve seen here recently.

© 2015 Steven Schwartzman

Written by Steve Schwartzman

January 21, 2015 at 5:10 AM

A closer look at frostweed ice

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Frostweed Ice Close 9539

Click for greater clarity and considerably larger size.

When I went out on the freezing morning of January 7th, it was to find “conventional” ice formations like the icicles and freezing creek you’ve already seen here and that many of you know so well from living in places with cold winters. To my pleasant surprise, I was also rewarded with dozens of frostweed plants, Verbesina virginica, that were doing their ice trick. Even though I’d taken lots of pictures of that when the temperature dropped below freezing exactly one month earlier, I couldn’t resist the chance to take another round of photographs of the strange phenomenon. I chose today’s view from the January 7th session because it’s unlike the one I’ve already showed from the December 7th outing. In particular it’s a lot closer, so you can see more details in the striations of the ice. If frostweed ice is new to you or you’d like a refresher, you can follow the last link to find out how this ice gets created.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

February 5, 2014 at 5:57 AM

Ice is white, and so are frostweed flowers

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Frostweed Flower 0806

While we’re on the subject of frostweed, Verbesina virginica, let 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 in the sunflower family, so the larger white areas are ray flowers and the smaller ones of a creamier white are disk flowers.

Today’s picture is from Rain Creek Parkway in my northwest Austin neighborhood on December 6th. Given how late in the year that was, these flowers were beginning to dry out and turn brown, so I had to scrounge a bit for a presentable bunch. Even at that late date, however, some frostweed buds were still emerging. Here’s a closeup of some:

Frostweed Buds 0845A

If you’d like a reminder of how nice frostweed flowers can look in their prime, and how they appeal to insects, check out this post from 2014.

© 2016 Steven Schwartzman

Written by Steve Schwartzman

January 13, 2016 at 4:57 AM

Frostweed debuts its ice trick for 2012

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Frostweed Ice 1594

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 frost begins settling 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, the first good freeze can cause it to draw underground water up into its base. Now for the strange trick: the exterior of the part of the stalk near the ground 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).

I took this picture of the fabled frostweed phenomenon yesterday morning in Great Hills Park. The sun had already been climbing for a couple of hours, and as its light reached the frostweed and the temperature rose, the ice began to melt. You can see that the narrow cone of ice that formed the right-hand peak of this formation had come loose from the frostweed stalk and was leaning far enough over that it would soon fall off. The whole left side of the ice already looks partially detached from the stalk as well. In the mild climate of Austin, frostweed ice rarely makes it through the morning, and yesterday was no exception.

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

© 2012 Steven Schwartzman

Written by Steve Schwartzman

December 12, 2012 at 6:19 AM

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