My Basic Garden Rule

HOW DOES YOUR GARDEN GROW

By Kit Flynn
Columnist

Recently, I had an email discussion with a subscriber that reinforced my contention that garden rules should be strict in nature but few in number. Everyone must follow their own guidelines on how to pursue their personal aims, as set for establishing and maintaining a garden. And this is not easy as it’s imperative to keep in mind that gardens are unnatural creations, ones that go against that which nature would like to produce.

So often I hear people contentedly exclaim that they are working with nature when gardening, and I quietly look at them with astonishment. Firstly, gardeners place plants near one another that would never occur in nature. In the second place, we’re using many plants that are not what nature produced; botanists have so hybridized many of our garden plants that we’re no longer familiar with their ancestors.

My basic garden rule is this negative: Never plant invasive plants. And, if you do, be prepared to rip them out. In the native plant world that seems to thrive in the minds of those living in Chapel Hill, the invasives are all “exotic” (i.e. foreign) plants, ones we are intent upon installing in our gardens while ignoring the innocent native plants that are non-invasive and therefore defenseless. 

Let me break this news to you: There are invasive plants to be found in both of the “native” and “nonnative” categories. Just because a particular plant is nonnative doesn’t mean it’s invasive. Look at camellias, gardenias, and lilies. With the exception of the dreadful Rosa multiflora, roses are on the non-invasive list – and some even have R. multiflora in their genetic makeup but do not take after their obnoxious relative.

Poison ivy is a native plant that is both undesirable and invasive. Grow it at your peril, along with Virginia Creeper, Parthenocissus quinquefolia, a vine that has few redeeming values. Its berries are poisonous, its sap can be an irritant to our skin, and it chokes out other plants as it wends its way using its aerial roots. Tulip poplars, Liriodendron tulipfera, while not considered invasive, are heavy seeders. Because my neighbors had them, I was constantly pulling out seedlings – numbering in the hundreds. These massive trees belong in our forests, not in our suburban gardens.

It’s also quite challenging to determine what is a native plant. Arbitrarily, those plants brought over by the original settlers are now considered “native.” Magnolia grandiflora is actually native to one small area in Eastern Carolina yet is supposed to be native when planted in the Piedmont. This then begs the question: Are plants native to California permissible to be planted here?

Plants travel, frequently from the west coast to the east. Plants also will hitch a ride – this is the way some of our worst exotics such as Microstegium vimineum, an invasive plant that I wouldn’t wish upon my worst enemy, arrived here. It has no redeeming features as even the deer refuse to touch it.

I’m assuming that if you’re reading this article, you periodically shop for plants, and here you have to be on guard, as even the most reputable nurseries can sell plants that can misbehave in our gardens. For several years, I sighed over photos in garden catalogs of the exotic Clematis terniflora, also known as Sweet Autumn Clematis. Fortunately, I didn’t buy it.

This clematis grows aggressively, but worse, it’s an extraordinarily heavy seeder, spewing seeds that all seemingly sprout. Plant this clematis, and you will have it for life. Keep in mind that, unlike Microstegium, it is a beautiful plant. One garden outlet has sold it to unsuspecting gardeners for years, despite consistently warning that this exotic beauty is highly invasive.

With research, I quickly came upon a native clematis that climbs but is not a wanton seeder. C. virginiana is not as breathtaking as C. terniflora, but it will not attempt to take over the garden.

The Sarah P. Duke Gardens is to be commended for replacing their famous wisteria exhibit with our native species, W. frutescens. Completed in 1939, the pergola, now known as the Cindy Brodhead Pergola, held the showy, exotic W. sinensis, the Chinese wisteria. It was gorgeous – and took an army to contain. When the metal framework of the pergola had to be repaired in 1914, the horticulturalists determined that the native wisteria should replace the Chinese wisteria. This was not an easy decision, as the native wisteria is not as awe-inspiring as the Chinese one. The smaller flowers are fewer in number, thereby dissipating the dramatic quality of the exhibit. Still, it was the right decision.

The point I am making is that there are good and bad plants for the garden, with the stress being “for the garden.” Even poison ivy has redeeming qualities in the wild, as birds love its seeds, and the leaves turn a lovely color in autumn that the early settlers sent back to be planted in England. Tulip poplars aren’t “bad” trees. They are simply unsuitable for a suburban garden.

Removing invasive plants is not enjoyable, whether you’re hand-pulling them out or saturating them with glyphosate. I always avoided any plant that carried the description of “aggressive,” “enthusiastic,” or “adventuresome” as this was a clue that perhaps that plant would be promiscuous in my garden.

The NC Native Plant Society states, “Some indigenous plants are certainly more aggressive than others but that doesn’t make them invasive.” While I would contend that this is the equivalent of splitting hairs, I would also add that aggressive native plants, such as goldenrod (Solidago canadensis) or common milkweed (Asclepias syriaca) should only be planted after careful consideration. In the wave of efforts to save the Monarch Butterflies, friends planted common milkweed, only to have the plant aggressively expand.

So this is my dictum: Be wise on what you plant, as most plants have endearing qualities with some drawbacks. After all, that gorgeous rose can carry painful thorns.