Gardening in a Changing Climate
A reflection on how our landscapes might fare in the coming century.
I recently posted something I probably shouldn’t have on the Gardening in Georgia Facebook group. I asked if anyone was considering how climate change might impact their gardens and plant selection. I knew it would be “stirring the pot” because of the controversial nature of the topic. The discussion is here: https://www.facebook.com/groups/928192903922370/search/?q=climate
I’ve asked similar questions on pages more aligned with environmentalism, like ones associated with native plants and pollinators. But Gardening in Georgia is made up of more “backyard” garden-lover types. I think it’s a more representative sample of the general population. Those are the people I’d like to reach, knowing full well the chances of changing their minds are about as likely as me winning the Powerball.
I fully expected the climate deniers, I mean, like most issues of our time, everything, including science, is politicized, and we’ve all aligned ourselves and our beliefs into the two obvious camps. If you vote Democrat, you believe climate change is an existential threat, but if you identify as a Republican, you deny that it’s a big deal. Or more specifically, many conservatives actually believe that climate change IS happening, but is “natural” and unrelated to human activity. I received many replies to that effect.
At least it isn’t flat-out denial. By acknowledging that you believe the climate is changing, yet not attributing that change to humans, you recognize that humans will be forced to adapt and change. And the “natural” argument is more complex to challenge because Earth’s climate has always fluctuated. To understand how current (or Anthropogenic) climate change differs from natural fluctuations, one must consider a “Deep Time” perspective.
This is hard for us because our lifespans are so short; we can’t grasp “millions of years”, we can barely grasp a human lifetime. But let me stress this point; regardless of whether climate change is caused by humans or not, even if we were to stop all burning of fossil fuels today (which we aren’t), the climate will continue to warm during our short lifetime.
And it requires us to understand the basics of how the carbon cycle works and how adding fossilized carbon alters its current composition. This is carbon that was deposited, in some cases, back in the Carboniferous Era, a time when the atmospheric Carbon concentration was ~1,500 ppm (today it's ~420 ppm).
As I’m not a scientist, I’m not going to explain why atmospheric Carbon Dioxide concentrations affect Earth’s climate. But I will provide a link to a helpful video on it:
Look, I know I’m preaching to the choir… And I’m fully aware that we aren’t in this position of climate denial because people haven’t heard the science. Experts have been sounding the alarm for decades; the real reason people mistrust science is because of a larger breakdown in trust that affects all areas of society. But I digress… those issues are for a different day!
A major problem in communicating an idea like climate change is that it’s hard to point to one single catastrophe, one event that proves unequivocally that the climate is indeed warming. We are just here to witness a tiny nano-blip of Earth’s history. It’s extremely hard to grasp the bigger picture. But we need to exercise our imagination and attempt to understand things that aren’t necessarily intuitive.
Like I said, I’m not a scientist, and I find it challenging to read primary source material, but I do have trust in those who are. And the consensus among the people who devote their whole careers to this kind of research is that there is a relationship between atmospheric Carbon Dioxide levels and global temperatures. Why is there a breakdown in trust between the educated classes and the working class? This is a question I think about nearly every day. I have no answer…
So what does all this have to do with my garden here in Georgia????
Heat not only exhausts people, it also exhausts plants. Have you noticed that during prolonged heat waves, our flowers stop blooming and appear lackluster or “tired”? Growth slows, and foliage and flowers fade; plants do this to combat the ill effects of heat. For an easy-to-digest article on heat-related stress in plants, check this out: https://www.kansascity.com/living/liv-columns-blogs/kc-gardens/article278167877.html
I’m making a distinction between “temperate” plants and “subtropicals”. Many of the stalwarts of the North American landscape, like Monarda, Echinacea, Phlox, Dianthus, and Baptisia evolved in temperate regions with 4 distinct seasons. It is this category of plants that I’m most concerned about. By the way, this includes all our deciduous forest trees, like oaks, hickories, and tulip poplars.
Btw, here is an additional article on how horticulturists are adapting to climate change: https://eos.org/articles/as-climate-changes-so-do-gardens-across-the-united-states
Unlike plants from the tropics and subtropics, temperate plants require a period of winter dormancy, the degree of which depends on the genetics of that particular specimen. For example, a sycamore from Florida is probably going to fare better in my climate than one from Ohio. As we consider selecting trees (and other plants) for the future, we should definitely utilize genetics from warmer zones. I’m practicing this in my own yard. I got chestnut oak acorns from a population 60 miles south of Newnan in the hopes that they might have a bit better heat tolerance.
Subtropical plants, such as Hedychiums (ginger lilies), Elephant Ears, and many Hibiscus, will comprise an increasing proportion of gardens (at least where I live in Georgia). These plants, for the most part, can take these hot nights. In some ways, a whole new palette of plants will be open to us, perhaps even more diversity than we currently have access to. This is a blessing, but it doesn’t mitigate the loss of so many historically useful plants that will be lost. Climate deniers will invariably use this argument to justify fossil fuel use. I even hear people say, “Greenland will be the new breadbasket.” They are technically right, but do they fully understand that if that is true, then what does this mean for Florida, or our island nations? Do they really want their beloved forests, places where they hunt deer, to change so radically?
I find myself thinking way too much about all this depressing stuff. But I try to consider it from a “Deep Time” perspective. This transformation, albeit gradual, will alter the “look and feel” of the South. Our native forests will shift from predominantly deciduous trees to evergreen species, such as magnolias and pines. If you don’t think this will happen, I urge you to walk through the urban forests surrounding Atlanta. While you still see large deciduous trees like oaks, they are being gradually replaced by broadleaf evergreens, like Magnolia grandiflora, Prunus caroliniana, and numerous Asian species, including Mahonia and Nandina. It seems likely to me that the biggest winners of climate change will be exotics from Southeast Asia and other subtropical locales; they just seem to have better adaptability to hotter temperatures than our North American species.
Think about it. Imagine a South in which you can’t even grow native azaleas, white oaks, flowering cherries, or native dogwoods. Many plants just won’t be able to live here anymore, but many new ones will. It’s obviously a mixed bag. Life will persist and evolve, but we humans will inhabit a very different world than the current one.
As far as the debate I triggered on FB. The moderator threatened to ban all the climate deniers, but I urged her to reconsider. I believe the only way to change people’s hearts is through maintaining a relationship and dialogue with them. If they encounter ideas that challenge their worldview presented by level-headed friends (even just virtual FB “friends”), they are far more likely to at least reflect on their beliefs and biases. We need MORE encounters with people who disagree with us.
So I urge you to educate yourself about the changing climate. Even if you don’t understand the physics or chemistry, which I totally understand. I don’t fully grasp it either. But there are great resources online. I want to end by thanking Pam Knox, an agricultural climatologist at the University of Georgia, for providing me with many online resources and input for this essay. I also thank Connie Barlow, the founder of Torreya Guardians and a science communicator, for her input as well.