Arctic Cold and Piedmont Plants

Happy New Year, gardening friends. I’ve got several posts planned that I’m not quite ready to put up, but I can feel the worrying of my fellow piedmont gardeners as we face the coldest weather in 15 years.

Tonight, the temperatures will drop into the single digits at my house, and tomorrow, with full sun and no snow cover, the highs will not reach the mid-20s. That is serious cold for around here, no doubt about it.

It’s happened before

But this kind of drastic dip in winter temperatures happens to this region every couple of decades. I know; I’ve lived through them, and so have most of my plants.

Back in 1985, we had several nights of sub-zero lows in early January. It got down to -9 at my house. In that case, I think the plants fared better than Wonder Spouse and I did.

How much trouble are we in for?

So what can we expect to happen to our beloved plants from an arctic blast like this, and what can we do to help?

Native deciduous trees and shrubs will be fine

The short answer to both questions is not much. Native piedmont plants are deeply dormant at the moment. Dormancy means metabolism rates are slow. In deciduous plants, next year’s flower and leaf buds are still tightly shut, protected by tough outer layers of sepals and bracts that shelter tender inner buds. Native deciduous plants — trees and shrubs — will be just fine.

Native hollies will fare well.

Native hollies will fare well.

On the other hand, you can expect at least some damage to evergreens, even native ones. The degree of damage will depend on the location  and age of the plants. Native hollies might get some leaf burn, which means they’ll look unsightly until new leaves replace the old ones next growing season. But if those hollies are foundation plants beside your house, the warmth of your house may protect the shrubs from the worst of the cold.

Southern magnolias may be damaged.

Southern magnolias may be damaged.

Some of our native evergreens aren’t actually native to the piedmont region, however. For example, Southern Magnolias are actually native to more southern parts of the US. It is likely that you will see some damaged outer branches, especially higher in the trees. All the leaves may exhibit what amounts to the equivalent of freezer burn. They may look brown or yellow and just generally sickly, but new leaves will replace these next spring. Some outer branches may be killed. Don’t try to prune what you think are damaged areas until the tree starts to grow next spring. It is almost impossible to tell what’s really dead until growth begins.

The native wax myrtle shrubs often used by landscapers as foundation plantings and screens are native to our coastal plain, not the piedmont. They are described as “variably evergreen,” meaning that when they get hit with single-digit temperatures, they are likely to drop most or all of their leaves. Most of the shrubs will still be alive, but any screening benefits will disappear until the new growing season.

Florida Anise-trees may take a serious hit.

Florida Anise-trees may take a serious hit.

I am worried about the Florida Anise-trees (Illicium spp.) I’ve added to my landscape in the last five years or so. These are native to coastal areas of the deeper South, not North Carolina. I am expecting that, at minimum, branch tips will be killed. Damage may be more extensive, but I’m hoping the shrubs — now all well over 5 feet tall and wide — will not die to the ground. I won’t know until the new growing season arrives in a few months.

Those of you who grow camellias may see damaged leaves and/or dead branches after this cold spell. If you were wise and sited yours away from north winds, your camellias will fare better.

Non-native early bloomers

I fear the cold will be too much for the nearly open buds of Prunus mime 'Peggy Clarke.'

I fear the cold will be too much for the nearly open buds of Prunus mume ‘Peggy Clarke.’

Of course, the non-native trees and shrubs blooming and/or about to bloom in my yard are probably toast. My beautiful Prunus mume trees are blooming. Zillions of fattening buds were just about to burst open. I fear that this level of cold will likely kill all the flower buds. They are at too tender a stage. I’ve cut a number of bud-laden branches (the trees needed pruning anyway) and brought them indoors. I couldn’t bear the thought of losing all the flowers.

I'm hoping not all the January Jasmine flower buds will fry.

I’m hoping not all the January Jasmine flower buds will fry.

The January Jasmine may fare better. Current flowers and almost-open buds will fry, but this shrub hugs the ground. I’m hoping still-sleeping flower buds will survive.

Tender Perennials

The lantanas, beloved by butterflies, may well succumb to the arctic outbreak.

The lantanas, beloved by butterflies, may well succumb to the arctic outbreak.

Winters have been mild for the last decade. A couple of plants that I know to be tender perennials have died to the ground every winter, then sprouted anew each spring. A cultivar of lantana, the name of which is long forgotten, has been surprising me by reappearing every spring for the last decade. But this cold spell may kill the roots, especially because the ground is saturated. Winter rains have been abundant.

This cold spell will likely be the demise of the pineapple sages.

This cold spell will likely be the demise of the pineapple sages.

My pineapple sages have also been reappearing every spring for a number of years. Again, wet soils and single-digit temperatures will probably kill the roots.

This rosemary is somewhat protected by my house. Will that be enough? Stay tuned...

This rosemary is somewhat protected by my house. Will that be enough? Stay tuned…

It is also likely that some or all of my perennial culinary herbs will be killed. Rosemaries are likely victims; so are the sages and lavenders. Oreganos and thymes are usually more resilient, but if the wet soils freeze solid, roots of all will die.

The good news, I guess, is that I’ve got cuttings of rosemary, pineapple sage, and lavender growing in the greenhouse. I always like to have extras to give away. This spring, I may be using them myself.

The Bottom Line

Tonight’s cold will certainly damage some plants, especially if our wet soils freeze solid. But I’m not convinced that the cold will stick around long enough to profoundly affect our landscapes. The weather seers seem to think that tonight and tomorrow will be the coldest periods. By the weekend, my area is predicted to be in the low 60s with yet more rain.

Frankly, all this rain is more of a problem for me than the cold. I am grateful for every drop, especially after decades of drought, but it is much more challenging to complete winter landscaping tasks when the ground is muddy and the skies are leaking.

Stay warm and dry, everyone. Bring your animals indoors, and if you can, feed your local wild birds. They need all the help they can get during our wacky winter weather.

At least we don't have to deal with the frozen precipitation plaguing our northern neighbors.

At least we don’t have to deal with the frozen precipitation plaguing our northern neighbors.

 

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