Posted on September, 16 2007
Cheryl Aldrich has been involved in the retail garden business in Atlanta, Georgia for the past 17 years. She has been living in Atlanta, Georgia since 1982 and has noticed that the winters are much milder than they used to be. This has had an effect on the types of plants that people can grow in her region.
My name is Cheryl Aldrich and I am 46 years old. I hold a Bachelor of Science in Horticulture from Michigan State University where I grew up, but have been living in Atlanta, Georgia for the past 25 years. I have been in the horticultural industry ever since I moved here in the 1980’s. Though climate change hasn’t been totally detrimental to the business I am involved with, I have definitely noticed some big changes in the winter temperatures and the plant life we can now grow here.
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Observations - Oleanders in Atlanta
One of the main things I have noticed over the past several years is what a lot of people around the world are noticing as well—winters are much milder here in Atlanta. I remember the winters here in the 80’s when temperatures would occasionally dip below zero degrees (F). One winter it was 7 degrees below zero. But in the last 15 years, there has not been a really cold winter. I have not seen temperatures in the single digits in a long time.
There are natural drought cycles here and we are currently in one, though it started early this year. Late winter and early spring are usually associated with a fair amount of rain, but we did not get much of the early rain that we should have gotten. Because this past winter was dry, many people lost a lot of plants because they are not used to watering in the winter time.
Some of the changes I’ve noticed are related to the more tender plants that are now over wintering here. Some of these (ones we used to consider risky to plant, such as gardenias, jasmine, and angel trumpet) have been coming back every year and are doing quite well. These species used to be considered marginal and not likely to survive the cold winter temperatures. Who would have guessed that even oleander would make it through the winter now? We’ve had one at the nursery which has over wintered for 5 years in a row.
Long drought impacting the dogwood
Overall, there is probably an increase in the number and variety of plants that we can grow here, so the effects of climate change are not necessarily all negative from a gardener’s perspective. With the drought, however, people are more concerned now about purchasing drought tolerant plants, because don’t want plants that have to be watered all the time. During the summer drought period plant sales slow considerably, but we have actually had an increase in our landscaping/ installation business.
The Atlanta Dogwood Festival has been in existence for 70 years—it’s a huge deal here. For decades the city had a program of planting dogwoods all throughout the city. The sad thing is that, not only are a lot of the dogwoods doing quite poorly now, the annual festival is no longer in time with the blooming of the trees. By the beginning of April, which is when the festival takes place, most of the dogwoods are done blooming. These emblematic and beautiful trees have been ailing for the last 15 years, mostly due to the drought. An increase in air pollution is also a factor.
People are aware of climate change here and I think that they are starting to get more tuned into this. The fact that we can grow oleander year round now and that we’ve changed from a zone 7 designation to zone 8 (United States Department of Agriculture plant hardiness zone based in annual temperatures) has forced people to connect the dots.
Even though it has not negatively affected me personally, I believe that climate change is a very serious problem. If it keeps on going like it is, I think it will begin to impact this industry more and more. We all have a responsibility to do something about it.
Scientific review
Reviewed by: Dr Michael MacCracken, Climate Institute,
USA
Projections of climate change for the US have climate zones shifting northward, with the coldest winter periods becoming less intense and less frequent. Models also project that warming will be largest during the coldest periods of the year, especially as snow melts back. Over North America, the warming of the Arctic is also exerting an effect, for as it warms, there is less production of very cold winter air, and the production that does occur is over a shorter period, so it is less likely to make its way to the southeastern US. And since it is the collision of the very cold air from the north with the moist tropical air that leads to the strong spring rains, the observation of less rain is also consistent with expectations.
While most of the discussion about changes in vegetation discusses the projected changes in terms of shifts of ecosystems—or at least of their major components (the large trees), this observation by a trained horticulturalist is particularly interesting because she is observing differential shifts in species. Those of us who look at the large-scale changes know ecosystems can’t really move—indeed, each species has its own sensitivity to the climate and each will move at its own pace. Ms. Aldrich’s note identifies a number of species that are now viable—that is, the cold boundary for growing them has shifted to the north. And she notes the earlier flowering of other species (including the iconic dogwood), again indicating a shift in the conditions preferred by the various species.
As these shifts in the boundaries of species occur (and there are likely some species that are no longer viable in her region—so the warm boundary is also shifting north), traditional assemblages of species will be stressed (and may become more vulnerable to pests and fire and drought), and new assemblages of species that compete best under the altered conditions will become the norm. On the local scale, this will affect horticulturalists and landscaping—on the larger scale it will affect the overall vegetative cover.
References:
- 1. The types of changes expected in each region of the US were described in the US National Assessment’s regional reports (see: http://www.usgcrp.gov/usgcrp/nacc/background/regions.htm )
- 2. Recent trends in observed conditions are being summarized in a soon to be published report of the Climate Change Science program entitled “Weather and Climate Extremes in a Changing Climate” (draft version is viewable at http://www.climatescience.gov/Library/sap/sap3-3/default.php)
All articles are subject to scientific review by a member of the Climate Witness Science Advisory Panel.
