In the plant world, when does “full sun” not actually mean full sun?
When you live someplace that gets really, really hot for a really long time.
When we go to the garden shop, and our attention is captured by an interesting looking species that is new to us, we will often look for the little plastic pick that is inserted in the pot, or if it There’s a seed packet we understand, we’ll turn it over to find out more.
We’re looking to the biography of the variety to tell us how tall and wide the plant grows, how much water it needs, and how much sun it needs.
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And therein lies the kicker for those of us in the southern parts of the country.
Many species whose labels claim the plants can take too much sun will simply burn in most of Texas, or the Southwest desert, or other hot and sunny parts of the United States.
In the summer, these areas are treated to harsh sun – and high temperatures – for more than 12 hours per day.
This is a really hardy plant that can take that kind of exposure and still look fabulous.
So what does “full sun” really mean for those of us in the South and Southwest? How can we enjoy a beautiful garden without risking losing everything in the sweltering heat of July and August?
Those of us in zones 8a and above need to be careful about how much sun we give our plants—though some areas with a lot of humidity may have better luck.
We consulted experts from several states. Across the board, his advice fell into two main categories. Let us see what he had to say.
location, location, location
Every single one of our experts said that choosing a location for your plants is very important.
“‘Full sun’ means 6-8 hours of sun,” says Ron Bowen, coordinator of Master Gardeners at the University of Arizona Cooperative Extension. “And plants generally prefer morning sun.”
For species that may not be able to handle hours and hours of brutal sun exposure, Bowen recommends that you arrange them in a way that they get morning sun and afternoon shade.
University of Nevada Cooperative Extension Agent Angela O’Callaghan, who holds a doctorate in horticulture, agrees with Bowen.
His advice to gardeners in Clark County (home to Las Vegas) is to focus on directional sun exposure. “If you’re growing something for the flowers or, by extension, for the fruit, these plants will need eight hours of sun, but put them somewhere where they’ll get bright light from 6 a.m. to 2 p.m. she says. “Facing west might not be the best idea for these types.”
Bowen says some commercial producers have started adding heat tolerance information to their labels. “These labels have only been out for a few years, mostly in the South,” he says, adding that it’s smart to check these guides for additional information on what types of climatic conditions a particular plant can tolerate.
“Hopefully more producers will adopt heat tolerance labeling soon,” says Bowen.
Another common theme we heard from our experts was the importance of being smart about which species and cultivars you choose for your garden.
“If you’re willing to spend an inordinate amount of time and resources,” says O’Callaghan, “you can develop almost anything,” but does it really make sense?
If it’s not meant to be, it’s not meant to be
Enchanted by the mythical beauty of the azalea and perhaps remembering the heady scent of childhood visits to Grandma’s house, my neighbors across the street insisted on planting azaleas.
In Austin’s notoriously alkaline filth.
They hauled in acidic soil, added thick layers of mulch, watered obsessively and even misted. He lovingly tended the surrounding trees, which he hoped would provide the necessary shade and coolness for the spiny shrubs.
In short, they did everything they knew how to give Azalea a nice and loving home.
And yet, before summer was a memory, once-beloved azalea bushes were in the compost pile, replaced by much more boring but highly Austin-tolerant sage bushes.
Moral? Mother Nature did it all so that plant A would grow where it makes sense for plant A to grow, and so on. It probably doesn’t make sense that humans try to interfere with carefully laid plans.
Trying to force Plant B to grow in Plant A’s territory will result in a waste of resources and potentially endless frustration!
Check out the thought-provoking book “The Human Gardener” for another reason to follow Mother Nature’s blueprint.
Have you heard of Laredo, Texas? It’s hot there. This city near the Mexican border could reach triple digits by the end of April.
Martha Ramirez, an extension agent for Webb County, of which Laredo is the county seat, stresses the importance of selecting local varieties. “We encourage our residents to consult our catalog of native and adapted plants,” she says. “We’ve worked hard to identify plants that are either from here or have proven to do well in our growing conditions.”
Both O’Callaghan and Bowen agree. “Check your local university extension office. They usually have good publications for your area,” says Bowen. Read up and be an informed plant buyer, he says.
O’Callaghan cautions against relying on information you find at garden centers, especially chain organizations or big box stores. “You can’t believe everything you hear,” she says. She says the employees at these places work hard but are often learning on the job and don’t have as much information as you can by checking good online sources.
O’Callaghan also agrees that plant seekers should do their research before visiting a nursery. “You need to know your garden,” she says. “Know how your bare spaces are situated and learn ahead of time what types of plants can tolerate the conditions in your garden.”
Source additions to your garden from locally owned and operated garden stores, or if you go to big box or chain stores, have a list of native and adapted plants on hand so you know what will work in your environment and what not
When shopping, you can also take into account where particular in-stock samples were grown before they made it to your local shop. For example, plants propagated in upstate New York or Minnesota may not do so well in Phoenix.
when in Rome…
Now that you’ve probably learned a little more about choosing and placing sun-loving plants for your Southern garden, perhaps it’s time to do some more research for specific species and cultivars that will take the heat.
Make a list, check it twice. Head to the garden store with your newfound knowledge and just maybe, come July, you’ll have attractive, rich greenery instead of brown sticks.
It is just a matter of choosing the right plant and planting it in the right place. And knowing your climate, of course.
As O’Callaghan of Las Vegas puts it, “All our sun… it’s not like Maine!”
Southern gardeners, we’d love to hear your experience with “full sun”. How many plants have you inadvertently fried? Do You Trust the Sun-Exposure Recommendations on Plant Labels?
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© Ask the Experts, LLC. All rights reserved. See our TOS for more details. Originally published on June 2, 2017. Last updated on April 3, 2023. Uncredited photos: Shutterstock.