We all feel the wind chill, but does it have any impact on plants? – Mike Lill
Good question Mike, as there are many gardeners out there who surely wonder if those subzero numbers are laying a beating on their landscape. We’ve certainly seen our share of wind chill maps lately, and we’ve all felt it walking around. But the answer to your question is no! Plants are not concerned with our ‘feels like’ maps.
Wind chill only has an effect on warm-blooded animals (that includes you, human). This group of life must maintain its own body temperature for survival. When we’re outside in the cold, the body is working hard to keep our temperature regulated (the same can be said in the summer when it’s hot). The colder it gets, the tougher it is for our bodies to keep up. If you’re exposed, the body will start sacrificing the extremities and will retreat to the core to protect your vital organs. But when you add wind into the mix, it accelerates the problem. The wind whisks heat away from our skin, removing our protective coat of warmth and putting ourselves at risk for frozen flesh (frostbite). That’s why layers are so important when you start seeing -20 or -30F wind chills. Any surface that’s not covered up will be at risk of freezing.
We need clothes to make it out there in harsh conditions. If we weren’t an inventive species that have developed ways to adapt to environment, we’d be out of luck and would need to live in more temperature locations. Mammals like polar bears can do without their North Face vests, because they have thick fur and more importantly a thick layer of fat coating their bodies. If you want to throw on a few hundred pounds of fat around the exterior of your body, you’d fare better than the average human in a New England winter.
However, plants don’t follow these rules. They don’t strive to keep themselves at a particular temperature all the time. The same can be said for your car’s radiator or a brick on the ground or a cold blooded animal (such as a reptile or amphibian). Anything that doesn’t need to produce its warmth to survive. What matters to all the above is the actual ambient air temperature. Plants tend to grow in places where climatology (general weather over a long period of time) allows them to succeed. Anything growing in southern New England is going to have a range of about -20F to 105F. Pretty remarkable if you think about it! Some don’t like that entire range and live in more ‘niche’ locations (think alpine flowers). But it’s always the air temperature itself that dictates the plants survival.
Some plants have different mechanisms for dealing with the cold. This photo of some backyard rhododendrons was sent in by a viewer, Bhaskar, to show how they shrink their foliage down when it gets colder.
That’s not to say that wind doesn’t matter! Strong winds can whisk not just heat away, but moisture. Plants are interested in that moisture, and a very windswept winter can be damaging for them (especially evergreens). Plus a windy storm can rip trees and shrubs apart if it’s really roaring out there.