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Monday, November 29, 2010

Frost Flowers

This morning I headed outside with the camera, as I was heading over to the community mulch pile to pick up a load of mulch. It was a frosty morning, a degree or two below freezing. I only walked out of the garage for a moment, but something caught my eye -- an interesting flash of white:


I wasn't expecting it, but some of the scarlet sage (Salvia coccinea) plants that I grow as an annual throughout my yard had produced frost flowers!


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This isn't too surprising, as I can depend on this species of salvia to produce frost flowers every year. What was surprising and unexpected was that it happened now, and not a few nights ago when it got really cold -- near 20ºF.



Frost flowers are actually ice that is formed under specific conditions that I apparently don't fully understand, but it involves the top of the plant being dead while the roots keep drawing moisture upward. As the water moves into the stems of the plant it leaks out and freezes. As the water continues to be forced upward the ice "grows" in interesting, complex, and beautiful ways.



The smooth, round curls look to me a lot like an old-fashioned ribbon candy.



You can see how the hairy, woody stems of the salvia have burst from the expansion of the ice -- or maybe the stems were burst from the previous freeze, and that's what allows the frost flowers to form?



I had dozens of these plants growing this year, yet not all of them have produced frost flowers today. Some of them had stems that were still intact too.


Now that I think about it, the plants that I'm seeing frost flowers on today might have been the ones that were still alive a week or so ago, but Thanksgiving's hard freeze should have killed them.



Maybe the key is to have one freeze to kill the plant, then a few warmer days, then another freeze (as long as there is moisture in the ground) to produce the "flowers".



Whatever the exact cause of this phenomenon, I'm glad I didn't miss it this morning -- these "flowers" are quite short-lived. More than just a touch of sunlight and they start to melt, their delicate structures disappearing, leaving lumps of milky ice with no hint remaining of what they had once been.



I'll have to keep an eye on the remaining salvias to see if they produce these flowers too, or to see if these same plants produce more.

If you're out early on a cold, snowless morning, keep an eye out for these flashes of white. As beautiful as they might be in photos, the delicate intricacy of frost flowers is best experienced first-hand. I still get excited when I discover them in my garden!

2 comments:

  1. I have never seen anything like it. You'd think this would happen here, too (we even have Salvia coccinea). Beautiful phenomenon for sure.

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  2. Maybe it is happening there too, but you're missing it. The first year I saw this (5 or 6 years ago I think) was only because I happened to have a pot of salvias on the deck, so saw it from the window. Since I think they only appear once per plant, it's pretty easy to miss.

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