Gardening, North vs. South by Bill Hayes

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Aiken has become a retirement destination for many. Some workers are transferred from northern limits and choose to stay. Others learn about Aiken from friends or read about our temperate climate and slower way of life in retirement magazines. Once here, they realize that gardening in Aiken is very different from their experiences in colder climates. It takes several years to accept some of our practices and a lot of plants and lawns can be lost along the way. Today we are going to discuss a few things that may help.

Let’s start with the lawn. The northern blue grasses and fescues cannot take our hot summers. They might make it through our cool winter as an over seed but who wants to cut and maintain grass all winter? OK, I know that some of you do it but remember, an over seeded lawn will slow the regular southern grass from developing in the spring. They are both fighting for the same nutrients. Two of our southern turf grasses, centipede and St. Augustine should not be over seeded. There are a couple of reasons for this. Both of these grasses may not go completely dormant in our mild winters. If that happens, the extra fertilizers that are used for the over seed will also affect the centipede and St. Augustine. This will lead to winter kill and a reduced lawn in the spring. The second reason is that over seeding requires that the primary lawn be scalped before seeding. Centipede and St. Augustine grasses have above ground stolons that can be severely damaged during the scalping process. Stolons are the long shoots or runners that carry the roots.

Cool season grasses also get a “winterizer” fertilizer to help them survive the very cold weather. The term “winterizing” means different things to different people so an explanation may help. Clemson states in their HGIC bulletin 1201 that fertilizer with nitrogen in the blend should be completely finished in August. We usually suggest that August 15th be the cut-off date in Aiken which means that we are past the application date right now. An extended warm fall might allow the date to extend to August 31st but do you want to risk it? Nitrogen, especially the slow release type, can stay in the ground longer and feed the grass right up to our first frost. October 15th is usually the earliest that we can expect extra cold temperatures. A frost on newly formed turf can kill the tender shoots and create problems in the spring. Some “winterizer” fertilizers only contain potassium which can help protect the southern lawns against cold weather damage. These should only be used after being confirmed by a soil test. Most of the soils in Aiken have sufficient potassium in a natural state. Finally, remember to give your lawn a little water during the winter. Zoysia and Bermuda will go completely dormant and should only need a 1/2″ of water once a month. Normal rainfall may take care of this. Centipede and St. Augustine should get 1/2″ of water about twice a month also depending on normal rainfall. Cold weather can cause damage by dehydration rather than temperature.

Let’s move on to flowers and the differences between growing them here and in colder climates. many varieties that do well in cool to cold climates will bake in our hot temperatures. Aiken is in heat zone 9 as described by the American Horticulture Society. This means that we get between 120-150 days above 86
degrees. Many of those days are in the 92-98 degree range and can be very hard on certain plants. Tulips, for example, are considered annuals in Aiken and will usually only last one year after planting. Some varieties will put out foliage but will not flower. Most lilacs will not make it here. They require a “chilling” period that we don’t have. Some southern nurseries are offering some varieties that “may” bloom in the south. These are “buyer beware” suggestions and should not be considered a recommendation. 1. Lavender lady, 2. Persica, 3. Miss Kim, 4. Dwarf Korean, 5. Ivory silk, 6. Angel white, 7. Sister Justine, 8. Superba, 9. Sylvan beauty, 10. Excel.

Peonies are also considered risky for this area. I have seen a number of excellent plants in Aiken but I’ve also seen some poor ones. Some of the large garden stores sell peonies in the spring and it may be worth a try to see if you have a magic touch. Some of our annuals such as begonias and impatiens may have to be re-classified. We get several reports each years that the previous year’s plants are coming up again.  Usually it is the impatiens that survive and that may not be god news since they tend to re-seed in unwanted areas. The continued debate about global warming may never be settled but, we are now  growing plants in this area that would not have made it twenty years ago.

Two more plants that are dependent on warm winters are oleander and eucalyptus. Both of these beauties do better in Charleston than here but do well in microclimates. Regular oleander needs six to eight hours of sunlight and hardiness zone nine temperatures. Aiken is zone 8a and a little too cold for oleander. If you have to have one for your landscape there  is a new variety called nerium oleander, hines hardy and marketing data states that it will do well in zone 8. Remember we are talking about USDA hardiness zones now and not AHS heat zones. Eucalyptus trees are very similar to oleander in that they love the heat all year. Our winters can cause severe damage to eucalyptus but, once again, a south facing microclimate might save this plant. If you have a sunroom, this plant can be grown in a container for several years and brought inside when cold weather threatens.

Now for an early reminder about pansies and violas. These two old standbys are fall and winter favorites and actually bloom into spring. We had several reports this year that they were blooming after the azaleas were through. Pansies and violas will do much better if they are planted early. By early, this means have your plants in the ground by October 15th. This will give them plenty of time to develop a strong root system and make it through the winter.

The Master Gardeners will be at the Farmers Market on Saturday, September 5th from 8:00 A.M. until noon to answer your gardening questions. See you there!