During the winter months, when horticulture staff are busy covering plants in advance of a hard freeze, a visitor might stop and ask, “How badly is it going to frost tonight?” Another might inquire about the frost hardiness of a particular plant that we are covering. I hear far more references to the term frost than I do freeze. But which is correct? It may be a cultural or regional choice to use one word or the other, but growing up on a working farm in Virginia, I learned at an early age that frost and freeze have very different meanings.
When we cover sensitive plants here at the Arboretum, we are attempting to protect them from a range of temperatures at or below 32 degrees F., the freezing point of water. Most of our plants are hardy to temperatures in the upper 20s for a short period of time (a couple of hours or so). However, when freezing temperatures are predicted to slip into the lower 20s or upper teens, we find ourselves going full throttle to cover and protect a greater number of plants. [Read more…]