As our temperatures have dipped lately any water left outside quickly freezes and turns solid. As many probably remember from middle school biology, freezing water and living cells don’t mix. When water freezes inside of living cells a whole bunch of damage occurs (Think Frostbite). So how is it that trees and other plants that are outside all night in these brutal temps don’t freeze to death? The answer is chemistry. During the months leading up to winter, plants begin to change not only the amount of liquid in their cells, but also the content of that liquid. During the growing season, much of the liquid in a plant is water, but the temps drop plants begin to no only dehydrate their cells to a certain extent, but all to include an almost antifreeze like mixture into them as well. In addition the membranes of cells within the plant become more flexible and resistant to puncture from ice crystals.
Plants certainly aren’t 100% resistant to damage from the cold. Smaller twigs and new growth can be damaged or even killed during the winter months. Generally this damage isn’t the end of the world for the plant and life goes on as normal next spring.