Late winter temperatures hampering plants’ flowers, new growth
by Marie Nesmith
Feb 19, 2012 | 3300 views | 0 0 comments | 21 21 recommendations | email to a friend | print
Jo Ann Dorsey waters the many plants she keeps in her Cartersville basement until weather permits moving them outside. 
SKIP BUTLER/The Daily Tribune News
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With temperatures swinging from the upper 60s to the low 20s in the past two weeks, area gardeners like Jo Ann Dorsey have been hard at work, trying to rescue flowering plants from cold damage. For Dorsey, who is the president of the Magnolia Garden Club, the recent cold spell has brought a touch of color into her Cartersville home.

"When we got real, real cold, I went out, picked my daffodils and brought them in," she said. "A lot of them were in full boom. I've got flowers in every room of the house almost. ... We often, here in Georgia, will have a late freeze and it will hurt them, but the plants are resilient for the most part. They'll come back [but it may] shorten the blooming time [for] these early things.

"But I don't know that I've ever really lost anything due to cold weather. ... I've tried in the past covering them up with towels or plastic or bushel baskets and that sort of thing but I don't do that anymore. I found out that it's not that advantageous to do that sort of thing. So I just let nature take care of them and just let them go. But if they are blooming and it's going to freeze, I'll sure bring them in my house to enjoy."

In addition to flowering bulbs, the cold also has affected many area plants that already were budding or blooming. With the recent cold snap, Bartow County Extension Agent Paul Pugliese has been fielding phone calls from those worried about their plants, some of which are flowering earlier than normal due to the 60-degree weather during the first weekend of February.

"Some examples of plants that we see blooming around town right now are things like saucer magnolias, star magnolias. I saw those blooming around the courthouse the other day," Pugliese said. "I had a call about a week and a half ago from a client that [said] her blueberry bushes were starting to bloom. Also some of the ornamental flowering cherry trees are starting to bloom in some cases. Camellias are actually a little bit more cold hardy and the worst thing that happens with those is the blooms that are already fully opened might turn to mush. But the buds that haven't opened yet will continue to bloom during those warm spells and that's actually normal as far as camellias are concerned. They're supposed to be blooming or starting to bloom this time of year. The same thing for your Japanese magnolias. They do tend to bloom this time of year and [it] actually is not too far off from normal. And because they are such early bloomers, quite often you'll get a few flowers that will get knocked off because of the cold or turn to mush on you, but they'll continue to bloom all through this late winter period.

"So it's not a total loss in that sense because they never all bloom at once. And again, most of the things that we're talking about are ornamentals. So the worst thing that can happen is you're going to lose a few flowers but it's not going to kill the plant by any means. Now for fruit trees that becomes more of an issue. It's not going to kill the tree but that could affect their yield for going into later this year when they start bearing fruit because if those flowers die then they're not going to pollinate and they're not going to bear fruit. So that is an issue for blueberries. That's a major problem for cherries. Actually that's one of the reasons why we don't have a lot of cherries growing in Georgia because we tend to get late cold snaps in the spring and cherries are one of the first ones to bloom. So it's just not a good climate for growing cherries here as a general rule."

Looking toward the future, Pugliese said another cold spell always is possible, with the last frost date in Georgia usually falling around April 15. Along with exposed blossoms, a plant's new growth also would be vulnerable to falling temperatures.

"That new growth, even like your hollies and your evergreen trees and shrubs and things like that, that new growth is very tender and very susceptible to freeze injury," Pugliese said. "Even crape myrtles, sometimes they'll start leafing out in early spring and if we have a late frost after they've started to leaf out or break bud, those leaves will get burned. If the plant is healthy as a general rule they can tolerate getting burned once or twice in the spring and they'll still be able to grow out of it. But if it happens too many times in a row, you can wear out those buds in that plant and it exhausts all of its resources as far as trying to put out new buds.

"In some cases you can get major die back or limbs that will die because of that. You're not going to have an entire plant die as a general rule but the more often that happens, the more stressful it is and the more likely those branches or tips of those branches will die back. So generally, we tell folks, 'Just wait until the last frost has past, usually toward the end of April or early May to do any of your pruning to take out those dead branches because then it will start leafing out again and you can tell how far to cut back to remove any burned or injured [branches] as a result of a cold injury.'"

To give them their best chance of survival, Pugliese recommends cultivating "healthy" plants. Along with fertilizing and hydrating the plants, he said gardeners also need to properly prune shrubs and trees and keep insects and diseases under control. Placing mulch around the base of the plant also is important because it helps retain soil moisture, enabling the flora to be more cold tolerant.

"Anything you can do to keep a plant stress free is going to give it a better chance of recovering from any injury or any cold damage that might occur in wintertime," Pugliese said. "It's just like people. If we stay healthy, we eat right, we exercise, when we do get sick we're more likely to recover more quickly and have less long-term problems as a result of that. We've gotten quite a few calls from folks who have things blooming a little bit earlier, maybe than usual, and again there's not a whole lot you can do about it. Covering plants when we get down into the 20s really doesn't do a whole lot of good. So you're wasting your time if you're going out and covering things if we go any lower than a few degrees below freezing.

"If you do cover a plant that's small, you could protect it if you could anchor that cover all the way down to the ground and trap some of that heat from the soil and kind of have like a greenhouse-type effect, that's kind of the idea there. But at most you might trap in 2 or 3 degrees of protection on that plant. And again, if we get any colder than that, below freezing, it doesn't matter what you put out there as far as the cover. Without a heat source, you're still going to have cold entry. So generally, I tell folks, 'Don't waste your time with covering plants unless it's going to be a light frost right around 30 degrees.' Getting closer to later in the spring, it might be worth it if you've got some blueberry plants or something that you want to protect in that situation."

Even though gardeners might not want to linger in their yards during the cold weather, this month is a favorable time to plant. While fall is the most ideal, planting in February also allows the plant's root system to begin establishing prior to Georgia's summer heat. With this in mind, Georgia recognized Arbor Day on Friday, with Bartow County Master Gardeners helping the Bartow Environmental Program distribute 2,000 free yellow poplar and persimmon seedlings.

"When you buy plant material from a nursery, quite often those are held in maybe a shade house or greenhouse conditions, which obviously is artificial," Pugliese said. "It's not a true reflection of the outdoors. So sometimes those plants are leafing out a lot earlier in a nursery situation and they haven't really been acclimated or hardened off to the cold just yet. So what we tell folks is that if you're going to do any spring planting of ornamental shrubs and trees to make sure you put them in a sheltered location like a porch or some area that has like an overhang to give them a little bit of protection for a week or two to acclimate them to the cold before you put them into the ground. But even then, the worse thing that can happen is you get a little bit of burn or the tips die back as a result of cold injury and you just prune that out later in the spring and correct that.

"That's no big deal. ... [For] bare root, dormant trees, the sooner you get them in the ground the better because you don't want those dormant trees to dry out if you leave them out of the ground because they don't have any soil on those bare root plants," he said, referring to seedlings like yellow poplar and persimmon. "So they're very prone to drying out. So the sooner you can get them in the ground and keep them moist, the better of a chance they're going to have as far as surviving and getting established later this spring. So as a general rule, when it comes to planting, sooner is always better than later when it comes to spring and especially when things are dormant. Actually we still recommend the best time to plant anything is in the fall. That way it has all winter to be acclimated and established and then it can go through whatever crazy weather we have in the spring and usually do just fine."

With the Bartow County Extension Office serving as a resource to gardeners yearlong, Pugliese urges residents to obtain fact sheets from their office -- 320 W. Cherokee Ave. in Cartersville -- and to carefully consider each fruit tree variety before purchasing.

"Whenever we talk about warm winters and problems with late frosts, this is always a great opportunity for folks to think about or make sure they do their homework before they buy plants," Pugliese said. "The most important things when we buy plants is to look at it's cold hardiness or the zone that you live in -- this part of Georgia is Zone 7B. So when you buy plants, you need to look for that cold hardiness zone on the tag to make sure that it's a plant that's adapted for this part of Georgia. The other thing, too, is there are a lot of fruit trees that I see sold at local nurseries. Those fruit trees quite often you can grow ... but there's a lot of variation in variety. Some varieties bloom earlier than others. So if you do your homework and find out which varieties are later blooming, quite often you'll find that if you use those late blooming varieties that you'll have less of a problem or less of a chance of cold injury and more likely to get a fruit crop in the season.

"Of course one of the things that we do is we have fact sheets through the extension office that people can [view] and the biggest thing is fruit trees. That's probably the No. 1 issue because you're actually trying to get a crop in on something like that. We have a publication on blueberries. We have one on peaches and plums and pears and apples, just about every fruit tree you can imagine. And in that fact sheet that we have, we list recommended varieties for north Georgia specifically. So we kind of do the homework for you, and if you pick from that list of recommended varieties, you'll do much better as far as not having problems with things blooming too early and avoid that problem in the future because sometimes like I said there's a lot of varieties being sold out there that may not be the best suited for Georgia or at least north Georgia."

For more gardening information, contact Pugliese at pugliese@uga.edu or 770-387-5142.