Garden Myths Debunked: Part 1
Disclaimer: This article is based on my personal opinions. I base these opinions on my experience, observations in the garden, and the science of horticulture. Hopefully I will not step on too many toes and will be able to inspire discussion of these topics.
Myth 1: Native plants are “better” than non-native species
This one has always bothered me but really got under my skin during the drought a couple of years ago when local politicians and the media jumped on the bandwagon. I often wonder what “native” and “better” means to people that make this statement. What exactly is their definition of native? Native to North America(pre or post European colonization)? Native to the southeast U.S.? North Carolina? The Piedmont region of N.C.? Some plants are native from the northeastern states down to Florida. Does that mean that a red maple grown in Florida will prosper in New York? How about windmill palm (native of N.C. and many other southeastern states) that was grown in southern Georgiaand planted in Raleigh? That palm is not going to be as cold hardy as a plant that was grown from seed of a plant that has acclimated for some time in our area. I could continue on about the “native” issue but my real beef is with the “better” than non-native species statement. How are they better? Are they more cold hardy? Drought tolerant? Better adapted to native soils? Natives are cold hardy, but should they not be? They evolved in their native environment. My problem with the cold hardy argument is that there are many non-native plants that are just as cold hardy as our natives. Who is to say which group of plants will evolve with our changing climate? As far as drought tolerance goes, there are native species that are, and some that are not. Non-natives are the same way. Native plants are certainly well adapted to our native soils, but is the soil around new homes or shopping centers the same as the soil in their natural environment? After the rich topsoil is removed, compacted sub-soils remain leaving an environment much different than what the plants is used to. Some natives can still make it here, just like some non-natives. I have no issue with native plants or gardens primarily comprised of them. We carry many natives here at the garden center. I do have an issue with poor information misleading gardeners and swaying opinions. This topic probably deserves an article all of it’s own, but I will leave it to this for now.
Myth 2: Clay soil “sucks”
Most of us in wake county (with the exception of those of you in Fuquay who have a more sand) have a lovely red clay subsoil. I talk to a lot of customers that can not stand to plant in the clay and actually believe that it is a bad soil. I can understand the attitude towards clay from a planting standpoint. It can be hard if dry, sticky if wet, stain your clothes, and can be a beast to work with if you have a lot of rocks (using a pick instead of a shovel to dig holes makes it easier). These negative attributes do not mean that clay soil is “bad” by any means. Without getting too in depth about soils, clay has a high CEC (cation exchange capacity). What the heck does that mean? Each clay particle can hold on to a large amount of nutrients, much more than that of sand. Basically, a well amended clay soil is a good thing. You can tell a lot about clay by its color. It is pretty easy. Red clay is good. Watch out for grey and yellow though. Grey and yellow are good indicators of poor drainage.
Myth 3: A wall of one species plant as a privacy border is a good thing
Actually, a wall of one plant, either for privacy or any other use, is a bad idea. This is called a monoculture. Think about a row o fLeyland cypress (the tall evergreen commonly used for screening). There is no genetic diversity there at all. All it takes is an outbreak of a fungus, bacteria, or an insect infestation to seriously damage or kill an entire planting. It becomes even worse when the target plant is as popular or over planted like Leyland cypress. Landscapers and gardeners are learning about the issue with Leylandsand are steering towards ‘Green Giant’ arborvitae as an alternative. In the short term, this is a good move, but long term the same thing will happen again if plants are used in mass. It is not necessarily an issue with the plant, but an issue with the mindset of using one species. The better way to approach a screening border or hedge is by mixing groupings of different species. Not only is it better for the long term health of the plant, but it is more attractive and biologically diverse.
Myth 4: We can feed plants
This one is pretty simple and a bit of a pet peeve of mine. We can not really feed plants. They produce their own food through photosynthesis. What we can do is supplement their nutrition through fertilizers. Those supplemental nutrients and micronutrients can be important to plants in poor soils and very beneficial to heavy bloomers.