Sunday, January 8, 2017

Spanish Moss Cold Hardiness II

Tillandsia usneoides that spent much (but not all) of the winter of 2015-16 outdoors in Mansfield, Connecticut.
A while back I wrote about the cold hardiness potential of Tillandsia usneoides (Spanish Moss). Last winter was a very warm one, and for a while it looked liked some experimental clumps of T. usneoides, the hardiest bromeliad, might make it through a whole year outdoors in New England. A specimen brought indoors on February 10, 2016, perked up in a cool greenhouse with no sign of frost damage.

However, one of the worst cold snaps in recent years started just a few days later, with five days around the weekend of February 13 not seeing temperatures above freezing at all. The arctic outbreak reaching a nadir with a day with high temperatures only reaching 10°F (-12°C), lows of -10°F (-23°C), and howling winds. Although this was only a brief interlude in a record warm season, it was enough to kill all the T. usneoides material that was left outdoors.

Periods of more than a week with constant sub-freezing temperatures, or absolute low temperatures below 0°F (-18°C), seem to cause severe or fatal damage to unprotected Spanish Moss. This winter in Connecticut we've already experienced enough cold weather to cause almost total dieback, but I wonder if some year soon we'll have conditions where T. usneoides survives an entire southern New England winter, and resumes normal growth in the spring?