Posted on 28th Mar 2016
It has been a very unusual spring for most of the country. Overall it has been too warm too early in the season. Many of early flowering plants and even some of the later flowering sorts are growing. Some shoots are several inches tall now, in the last part of March.
While we all appreciate the early spring, the sunshine and warmer temperatures, there is no guarantee for this to continue. In the last few days we received numerous inquiries regarding how to protect plants that already sprouted and the potential threat of winter weather returning to some parts of the country.
Snow and a few days in the 30's most likely will not cause long term damage to shoots and the developing flower buds. If snow and temperatures in the 30's F return to your area do not worry too much, most established perennials are tough enough to survive. Danger to the flower buds can be expected if temperatures drop below 28F or if the cold is persistent for several days. If a freeze occurs, temperatures drop below the freezing point of water (32° F or 0° C), the water inside a plant freezes. Freezing can cause the plant cells to burst, resulting in loss of foliage. Spring blooms and early foliage may be damaged by late-spring freezes, but the plants themselves usually recover.
A good snow cover may protect the shoots. The least desirable situation are temperatures below 28F and no snow cover. If the weather forecast predicts such an occurrence a generous layer of straw may protect your shoots just enough, so you do not lose the flower buds. Now if the cold should damage your shoots and the flower buds, it is not the end of your plant. Your plant should grow axillary shoots a little later in the season and will grow out of the frost damage, though it may effect flowers for this season.