So far, winter has proven to be a test of endurance and wits for most people around the state. Because of the trend of relatively mild winters with only short bursts of cold and snow, we have grown unaccustomed to the bitter bite of winter. You’ll have to go back a few decades to find a winter as harsh as this one.
The question is, have we become so accustomed to mild winters that we might have some unexpected damage or death in the garden? To find out, we will likely have to play the waiting game.
I would bet that most gardeners have grown complacent in preparing their gardens for winter or even have felt secure enough to include trees, shrubs and perennials in their landscape that might not be completely hardy. I, myself, have plants in my landscape that push limits.
I’m expecting at least some damage to my Camellia sinensis tea shrub, as it is hardy to Zone 6b (or 7, depending on whom you ask). While technically I am in Zone 7 in Charleston, the zones are based on averages, and I can tell you that our sub-freezing temps are well below those expected for Zone 7.
Even hardier plants like kale gave up during the arctic vortex.
What are zones and what do they mean?
The USDA Hardiness Zone map delineates the country into areas based on an average of their lowest temperatures each year. When new map data are determined, the lowest recorded temperature for each year over 30 years is used to determine an average lowest temperature.
The map is accurate only when it is updated regularly. A new map was released a few years ago but was already a few years behind.
The averages are the categorized into zones of 10 degrees each, with a further breakdown in units of five that are denoted with the letters “a” or “b.” This means that if you live in Zone 6a, the average lowest temperature is between minus 10 and minus 5 degrees Fahrenheit; Zone 6b averages at minus 5 to zero.
Since these are averages, unfortunately you can’t predict how cold it will get.
What does this weather mean for gardeners?
As I stated, many of us have become complacent with mild winters and have given little thought to protecting our trees, shrubs, perennials and even overwintering vegetables from freezing.
Unfortunately, hindsight really is 20/20, and if you did nothing to protect your plants during the cold snap, you may see damage. I would bet that even plants rated for our zones or lower could even see damage.
One that I’m betting on getting calls about come spring is crape myrtle. This popular shrub dominates the South, but it has slowly worked its way north. Most of the ones sold in this area are hardy to Zone 6, but we live at the northern extreme of their natural limit.
Drops in temperatures can mean dead branches or delayed spring awakening. But as long as the crown at the soil level is still alive, the shrub will grow back.
I would also wait a while before doing anything drastic; crape myrtles can be late bloomers after harsh winters.
Many other plants, if left unprotected, also could see dead branches or even mortality. This article was inspired by Joan Steven, a Master Gardener and Master Naturalist, who called to tell me that she feared that her rosemary had bit the dust. I’m afraid that her assessment is probably true.
We also have grown accustomed to leaving tender bulbs such as gladiolus and canna out to fend for themselves over winter. It could be possible that for some their gig is up.
How do you protect against winter damage?
While it may be too late for anything killed or damaged during the last cold snap, it is important to know how to plan for future arctic episodes in the garden.
The first step in making sure that your garden does not succumb to winter woes is in plant selection. Be sure to check out the USDA Hardiness Zone Map atwww.planthardiness.ars.usda.gov/ to know your zone.
While it does not guarantee that you will not have damage, it will help reduce the likelihood. If at all possible, plant your more-tender plants in areas protected from wind, especially if they are evergreen.
Winter damage also can occur from drying out, especially in evergreens. This is best avoided by planting in less windy areas and making sure plants are well watered in the fall. Protected areas near buildings have the added benefit of radiating heat in the evening from daytime solar heating.
Mulching is also an important tool in the winter arsenal. This is one area where I know many gardeners have grown lax. Mulching provides a protection from the uneven freeze/thaw cycle we see in winter.
The gist of mulching is to keep the crown of the plant, where new growth comes from, insulated. It is important to know that it should be applied after the cold arrives, so that temps stay moderately cool. It should completely cover the crowns of perennials, and should also be heaped around the crown of tender shrubs, including roses.
If you fear damage to branches or buds of shrubs, covering them with a frost barrier will help out. You can buy special frost protection material, or things like old bed sheets or burlap will do.
The frost cover can be used both in the landscape and in the vegetable garden and will offer a few degrees of protection. As long as the crown lives, the plant will live. If not, enjoy your shopping trip.
Read the full article at the Charleston Gazette-Mail site.