On a cold day, when you want to know what the temperature is outside, look no further than your rhododendron bush. Thanks to a process called thermotropism, the leaves of this evergreen begin to curl as the temperature nears freezing and curl even tighter as it drops about another ten degrees.
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| Rododendron leaf curl at 30 degrees |
At about 30 degrees, the leaves of the rhododendron plant droop slightly and curl to about the size of a cigar. Thats when I know a warm jacket is needed and to watch out for ice on the roads while driving.
When the temps drop close to 20 degrees (or below), the leaves droop so they hang
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| Rododendron leaf curl at 20 degrees |
like pendants and they curl tightly so they look like green beans. Time to add a thermal layer before venturing outside!
As the air warms, the leaves will uncurl until they are flat, and raise up to a more
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| Add Rododendron leaf curl at 40 degrees |
horizontal position. As soon as rhis occurs, the temperature is 40 degrees or above. So just peek out your window on cold days at your (or your neighbors) rhododendron bush to get an idea of just how cold it is.
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