Friday, February 11, 2011

Frost Flowers

Frost Flower wrapping around a Pentas stem

Frost Flowers on Pentas

Frost Flowers on Pentas

Frost Flowers spread like wings from Pentas


Candy floss, cotton candy, spun glass, ribbon candy, wool roving, spun sugar, spun cotton:  all are ways to describe the delicate, crystal structures called Frost Flowers. 
A cool, rainy day followed by a freezing night provided the conditions needed for Frost Flowers to occur in my garden.  The soil was moist and not frozen.  The plants had viable roots which could conduct water from the warmer, wet soil into the stems.  When the air temperature plummeted to below freezing, the water in the stems expanded and the plants extruded the water.  Countless, tiny threads of ice were pushed out of the plant stem, starting near the base of the plant.  Variations in air temperature caused the waves of ice to bend, curl and twist forming fantastic shapes.  
If you touch a Frost Flower you will feel that it’s not solid like an icicle.  It’s frothy and fragile.  The ice of a Frost Flower will sublimate as the air warms.  Sublimation means that this ice does not bother with melting into a liquid.  From a solid state it will change directly into a vapor.  The magical Frost Flower will literally vanish into thin air.
In Texas, Frostweed, Verbesinia virginica, is known for making Frost Flowers. The common name is a clue!  In my garden, the Pentas produced the biggest Frost Flowers, but I noticed Frost Flowers on Salvia Indigo Spires,  Russelia and Plumbago.  We have had this phenomenon for three mornings in a row.  I noticed today that the white ice crystals began to appear around 0500 hours.  By 0800 hours, my husband and I were taking photos of the curling formations.  By 10:00 o’clock that morning, the ephemeral Frost Flowers had disappeared.
Frost Flowers on Salvia, Indigo Spires

Frost Flowers on Pentas

 
Frost Flowers on Pentas
My husband captured this image of Frost Flower on Indigo Spires

2 comments:

Holly said...

Wow, those are beautiful! Thanks for sharing. I have some of those plants in our backyard. I wish I had known about this. Maybe the cold is not over yet. I'll be out checking next time. Thanks again.

Milkweed Patch said...

Howdy, Holly! Thank you for your kind comment. We will have to be alert for these next winter. ~~~ Sally