FOR THE DAILY SOUTHERNER
Nancy H. (Tarboro) asks - The weatherman is calling for highs in the mid-70s over the next few days; what effect will this have on my ornamental plants and should I be concerned? Will the warm weather wither my plants?
The quick answer is: It depends. On how long will the warm temps last and will the temps drop gradually after the warm-up or will there be a severe & quick drop in temperature after the warm up.
In addition, it depends on the particular plants involved and your location, how your plants fare depends on how quickly cold temperatures return, how cold it gets, and other environmental factors.
A sudden drop to below-freezing temperatures following the warm weather in early January would severely stress many plants. But most plants should acclimate OK with a gradual return to more normal winter temperatures.
It is likely some flower buds will be killed. So we may see fewer blooms on flowering trees and shrubs this spring. That would be a grave concern for commercial fruit growers, as they will harvest less fruit if too many flower buds die. But for most of us, it just means we'll see fewer flowers.
With regard to your lawn, the good news, say turf specialists, is that warm temperatures in early winter encouraged root growth in existing lawns and strong establishment of young seedlings in new lawns planted last fall. The bad news is, if temperatures drop too fast, lush top-growth may be more prone to freezing damage. So you should avoid walking on lawns as much as possible until the soil dries out and grass starts growing again in spring.
While the picture is more complicated concerning fruit trees, in general, flower buds on fruit trees won't be as cold-hardy this year due to the combination of warm weather and fluctuating temperatures, say fruit specialists. Many flower buds could be killed if temperatures drop rapidly below freezing, reducing flowering in spring and fruit harvests later.
It's a similar story for ornamental trees and shrubs. Most woody plants have evolved to deal with a brief spell of unseasonably warm weather. With most woody plants in the Northeast, buds won't open during the first warm spell and then get killed by a return to cold temperatures because buds require a period of cold temperatures to break dormancy. But we now grow many ornamental trees and shrubs far from their native range. Some of these trees and shrubs have shorter chilling requirements, and may begin to flower prematurely if we have prolonged warm weather in winter. So we'll lose some of those flowers for this season, but the long-term health of most plants probably won't be affected.
There are a lot more details regarding warm winter effects on the following site: http://www.gardening.cornell.edu/warm_winter/
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