Frost Flowers- 2011

Ice Ribbon

Once again the frost flowers of autumn are amazing.  Every year around this time the first freezing temperatures create ice in the thin stems of the frost weed a.k.a. white crown beard (Verbesina virginica).  The ice is squeezed out through long splits in the stems, creating thin ribbons.  Some years these are delicate thick ribbons at the base of the plant.  Another year they may produce a series of "petals" radiating all around the stem like icy pinwheels. 


This year's "blooms" are the tallest we have seen.  The first hard frost on Saturday morning produced icy ribbons two feet up the stem, a striking sight of glistening white where there had been only dull gray stems before.  We walked along the driveway, photographing them as the sun's beams first let them glow.  After their brief moment of glory, like Icarus having flown too close to the sun, their icy "wings" melt like his wax and the drops fall to the ground.

Single stem split in fourths

The next frosty morning produced an encore, with ribbons now extending three feet up the stems.  This time the stems were split wide open leaving thin columns to support the dead heads for a few more days.

During the growing season, the crown beard and its fellow frost weed, yellow ironweed (Verbesina alternafolia) are unremarkable looking with tall winged stems, large leaves and small flower heads, rather like plain sisters of a sunflower.  They grow on roadsides and fence lines in the neglected soils.  I avoid mowing these strips, knowing that their brief moment in the sun will be worth the wait.

Past Posts are from  November 2010 and December 2009.
More detailed science is available these sites:
- biosci.utexas.edu 
- http://my.ilstu.edu, /~jrcarter/ice/diurnal/
-  http://my.ilstu.edu/~jrcarter/ice/diurnal/wood/