Lately, we’ve had a stretch of unseasonably warm weather in Asheville, so I’ve taken some time amidst the chaos of the holidays to get out in the yard and tackle a few projects. I have a condition called fibromyalgia, a pain amplification disorder of the central nervous system, and it messes with my stamina. Some days it’s a challenge to get moving, but for the most part, I’ve found some work-arounds to help me manage our .39 acre yard.
One trick: I tell myself that I will tackle one particular plant in a set amount of time. For instance, yesterday I gave myself 15 minutes to dig up as many roots of invasive Japanese Virgin’s Bower (Clemantis terniflora) as possible. Invasive non-native plants such as privet and bittersweet pull up easily if caught early. However, invasives such as Clemantis terniflora have hateful, tenacious roots that require muscle grease to dig up:
Another trick: I give myself a set amount of time to work on one section of yard. This way, I don’t feel overwhelmed. As a gardener, I spend most of my time weeding. It’s taken me years to get on top of the massive amount of invasive plant species trying to out-compete my native plants. As I’ve thinned the invasives in my yard, it has becomes easier to stay on top of them. I know it will be a life-long chore, but it’s worth it to me. The one place I’ve been most successful as an environmentalist is in my own yard. In my favorite book Bringing Nature Home, Dr. Douglas Tallamy writes:
“But now, for the first time in its history, gardening has taken on a role that transcends the needs of the gardener. Like it or not, gardeners have become important players in the management of our nation’s wildlife. It is now within the power of individual gardeners to do something that we all dream of doing: to make a difference. In this case, the “difference” will be to the future of biodiversity, to the native plants and animals of North America and the ecosystems that sustain them.”
Native plants have co-evolved with native insects, birds and other wildlife and depend upon each other for everything from pollination to food. They have developed ways to keep each other’s populations in check and keep their environment in balance. Invasive, non-native plants brought to this country by the nursery industry or by accident often have no natural predators to keep them from exploding and overwhelming our native plants.
My dear Aunt Oval, who nurtured my love of wildflowers, once told me about how deeply she regretted planting an English ivy plant — yes, one lone plant! — in her yard in the ’50s. By the time she died a few years ago, the English ivy had spread to over a quarter of her huge lot and choked out most of her native plantings in the back of her yard. Ivy will choke out any plant that gets in its way, including trees. It’s a plague, yet the nursery industry still sells it. Terrible. Friends, always be careful of what you buy and plant.
At the Botanical Gardens at Asheville, we have indoor and outdoor volunteers. To work outdoors, volunteers must be willing to undergo a very long and extensive training. That’s because so many invasive non-native plants look so similar to plants native to our area. Isn’t that just peachy? Someone once pointed me toward a great resource published by the Delaware Department of Agriculture called “Mistaken Identity? Invasive Plants and their Native Look-alikes.” I ordered a hard-copy of this book and have made great use of it. I’ve never once found a specimen of our native clematis in my yard.
At the Botanical Gardens, we eschew chemical herbicides and insecticides with very rare exception.* Our outdoor volunteers, as well as garden staff, spend a majority of their time weeding by hand the gnarly invasive plants that threaten our fragile native plant collection. The organic gardening philosophy that guides our behavior at the BGA is also one I take seriously at home. The main reason we don’t use toxic chemicals in the Gardens is for the safety of our guests – human, critter and insect. We also have two streams that converge in the Gardens, and we simply do not want to add to the pollutants flowing into the French Broad River.
“It causes more work for us, but we have people who visit who are relieved that they can lie in our grass and not have to worry about being poisoned,” said Jay Kranyik, BGA garden manager, my boss. “I consider dealing with invasive species organically to be taking the moral high-ground.”
The Toll of Invasive Plant Species
Approximately one-fifth of the plant species in Great Smoky Mountains National Park are non-native;. At the Botanical Gardens, it’s about one out of every eight. Some of these noxious plants were brought to the U.S. accidentally – in cargo vessels, for example. But most were introduced as ornamentals or for livestock forage without insight into how many would escape cultivation. With no natural predators, invasives have choked out many native plant populations.
This tips the ecosystem out of balance. Most life on earth depends upon plants that transfer solar energy into food through photosynthesis. Higher forms of life, in turn, are dependent upon the insects that eat the plants. For example, people depend on insects to pollinate plants and birds depend on insects for food, especially in the reproductive cycle of baby birds. The ultimate impact of all this interdependence is unknown, but that’s why the battle against invasive plants is important.
Dr. Tallamy explains the invasive/insect connection:
“It takes time – long evolutionary time spans rather than short ecological periods – for insects to adapt to the specific chemical mix that characterizes different plants,” he writes. Most insects have become “specialists,” adapted to specific plant food sources. For example, writes Tallamy, “Eastern tent caterpillars (Malacosoma americanum) are specialists on a single lineage of plants in the order Rosales; plants outside that lineage cannot serve as food for these insects, even in the face of starvation.” Who cares? The bats and birds that depend on these caterpillars for food.
Monarch butterflies are specialists to the milkweed plant, and that is exactly why they face such peril. Their caterpillars only eat milkweed and milkweed has started disappearing at a very alarming rate due to habitat destruction, farming, insecticide, and climate change. In nature, it seems that being a specialist and relying on only one type of food source would be dangerous, until you consider that if you specialize in a plant that other insects reject, you’ll have plenty to eat in a balanced environment.
You may be looking at your own yard filled with Japanese honeysuckle, English ivy, privet, bittersweet, etc., and feel completely overwhelmed and exhausted. You may also ask yourself if you’re waging a losing battle.
“One thing I remind our outside volunteers – we’re in it for the long-haul,” said Kranyik. “At one time the entire length of the parking lot used to be covered in periwinkle. The Gardens’ stream banks were covered in privet and multiflora rose. Every single tree of heaven over ½-inch in diameter is gone. We used to have hundreds of them.”
Let’s all keep plugging. We have too much at stake to give up.
* There are cases where we have a certified applicator treat invasives with chemicals but always as a last resort. For example we have to treat our hemlock trees (Tsuga Canadensis and Tsuga caroliniana) for the hemlock woolly adelgid, an Asian insect wreaking havoc on U.S. Hemlock populations.