Will cold damage my perennial plants?
Despite the recent snowfall in parts of the Miami Valley, spring is really coming — at least that’s what the calendar says. My daffodils and hyacinths say the same thing!
In fact, they made an appearance several weeks ago, sometime back in January. They are holding their own against Mother Nature and still look OK at this point.
Keep in mind that there is not a whole lot you can do to change the fact that some of our perennial plants have emerged and are showing foliage.
Bulbs that are showing now won’t completely die from cold temperatures. However, they may not look the best. A perennial such as iris that is showing foliage growth right now also won’t likely die from cold temperatures — they might just look a little ragged.
The key to understanding and predicting cold injury to plants in the spring has to do with the stage of growth for the plant.
Take, for example, the foliage growth that you are seeing on daffodils right now. Mine are showing about three inches of foliage. As I said, they have been like this since sometime in January.
We have had cold temperatures since they emerged, and they are still green. We have had a few really low temperatures, and they weren’t damaged.
The damage occurs when we have several days of nice weather that encourages new green TENDER growth. And then, the temperature suddenly drops overnight below freezing.
It’s that temperature drop combined with soft, tender green foliage that causes the most damage. In addition, this is cosmetic damage or damage to the foliage. This type of situation doesn’t damage the flower because the bud is not showing.
In the spring, when the flowers bloom and a frost or freeze is predicted, you can count on damage to the flowers. Flower tissue is tender and susceptible to frost or freeze.
In the winter, when flower buds are tight, they are typically protected from cold temperatures as they are dormant. However, some flower buds can only withstand certain levels of cold temperatures and may be damaged while dormant.
For instance, peach flower buds are cold hardy down to around -13 to -15. Temperatures in this area for a even a short period of time can cause death to the flower bud.
Back to your exposed daffodil or iris foliage, what can you do? If you want a perfectly green leaf with no damage, good luck. This is going to be quite a challenge unless we have perfect weather conditions.
You can cover plants with blankets or other materials to protect the tender foliage from cold injury. This is time-consuming, but if you have that kind of time and want to do it, go ahead!
I have come to the point in life where I tolerate some damage. Some, but not all. For instance, if my daffodils are in bloom and a frost is predicted, I’ll go out at night and cut all of the blooms and make giant bouquets in the house!
I can almost guarantee that we will have a period of warm sunny days that pushes nice, tender green growth, followed by a sudden drop in temperatures. I say almost because perhaps, for once, spring weather will be perfect — or at least the way we want it to be. Hah.
Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at bennett.27@osu.edu.