The Real Aliens in Our Backyard

This is a really good, critical information for our naturalized areas.

By Margaret Renkl - Contributing Opinion Writer

The future of this country’s wild spaces may depend on changing the way suburban Americans think about plants.

NASHVILLE — Our yard is separated from our backdoor neighbors’ yard by a small city easement. For the first two decades we lived in this house, our elderly backdoor neighbors kept a deep border of hardwood trees and woody shrubs on their side of the easement, a shelter for songbirds and a corridor for wildlife — deer and opossums and rat snakes and box turtles and red foxes and great horned owls, among many others.

When those neighbors died, a construction company bought their house and tore it down. Then they cleared the lot, edge to edge. The mature trees and plants in the easement weren’t bulldozed, though many of them died anyway, killed by the weight of construction equipment lumbering across their roots.

But nature, as you may have heard, abhors a vacuum, and new plants have sprung up in the easement: privet and bush honeysuckle and winter creeper and a host of other shrubs and vines. With so many of the big trees gone now, more sunlight reaches the new plants, and they have grown like something possessed, something determined to fill the gaps left by all the red maples, hackberries, poplars and cedars lost to development in this neighborhood.

You’d think I’d be happy about all this new green life. You’d think I’d be grateful that the warblers have a new place to rest on their long migration. But I’m not happy. I’m discouraged.

This kind of nature isn’t natural. Most of the plants now growing at the back of our lot aren’t native to Middle Tennessee. They’re native to other continents entirely. As aliens, they are poor food sources for our native animals and insects. A landscape populated by nonnative plants is, for wildlife, the equivalent of a desert. Worse, many alien plants are also highly invasive, choking out native plants and sending out their own seeds, some of which will settle and grow in wild places miles away from suburbia.

During summer, the easement behind my house looks as healthy and verdant as any natural place left to its own devices, but it’s nothing of the kind. The invasive plants are far too big for me to dig up, but I do my best to minimize the damage — cutting back buds before they can flower, pulling up seedlings, planting native trees and shrubs where I can. The project often feels Sisyphean.

That’s why I ended up tagging along with Frances Corzine on a cold, drizzly Saturday morning this month as she checked on the progress of Weed Wrangle, a coordinated effort to eradicate invasive plants in public parks and natural areas. The initiative was founded in 2015 by the Garden Club of Nashville with funding from the Garden Club of America’s Partners for Plants program. With the national club’s sponsorship — and the help of community partners like the Tennessee Environmental Council and Tennessee’s state park system — it has grown like kudzu, spreading to 60 other cities in Tennessee and to 12 other states.

This does not reflect well on me, but I have always associated the term “garden club” with tea roses and insecticides, pristine lawns and herbicides. When I confessed to being surprised by the garden club’s interest in conservation, Ms. Corzine laughed. “We’re not your grandmother’s garden club,” she said.

Clearly not. At Fort Negley, the site of a Civil War-era Union fort and the first Weed Wrangle site on Ms. Corzine’s list that morning, volunteers were spread out along stone fortifications on the hillside, gently removing ailanthus seedlings. At fragile historic sites, invasive plants like ailanthus, inappropriately nicknamed “tree of heaven,” pose a risk not only to wildlife and native plants but also to the site itself as roots push apart the very stones of the buildings that preservationists are working so hard to save.

Over at Nashville’s City Cemetery, our second stop, volunteers wielding a contraption I’d never seen before were attacking a bank of bush honeysuckle: An Uprooter, it turns out, is a miracle tool, part wrench and part lever, that makes it possible for a normal person to pull a small tree out of the ground by its roots. It dawned on me that if every homeowner in the country kept an Uprooter in the tool shed next to the lawn mower, the spread of invasive plants could be greatly slowed.

The relationship between backyard plants and the health of the nation’s wild spaces is a point that Cayce McAlister, a former president of the Garden Club of Nashville, was careful to make when I spoke with her by phone last week. Ms. McAlister was the inciting force behind Nashville’s first Weed Wrangle and is now an organizer of the national club’s efforts to help the program grow, eradicating invasive plants and replacing them with native varieties nationwide.

The idea for Weed Wrangle came to her when she took some garden-club guests from Oregon on a tour of Warner Parks, the 3,000-acre crown jewel of Nashville’s extensive system of parks and greenways. Ms. McAlister was lamenting all the bush honeysuckle, Bradford pear trees, Chinese privet and English ivy growing in that beautiful wildness, when her guests pointed out the same plants growing in nearby neighborhoods. That’s when Ms. McAlister had her brainstorm: “If we don’t tell people what these plants are, we’ll never get them out of our parks.”

But Americans are still buying nonnative plants, even highly invasive ones, from local nurseries and big-box garden centers alike. “Privet grows. Honeysuckle grows,” Ms. McAlister points out. “And people come back for more because it grows.”

Unless they learn not to. During the first four years of Weed Wrangle’s existence — a total of four mornings’ work — volunteers removed more than 150,300 invasive plants across Tennessee. But the benefits of the program expand far beyond the communal effort itself. “Volunteers have fun doing it, but the most important thing is that they go home and do the same thing in their own yards,” Ms. Corzine said. “And then they tell their neighbors.”

 

Good article Oya. Too bad we don't apply the same principles in our treed areas. HLS comes through to cut brush but they don't distinguish between native and non-native species plants. They don't uproot the invasive plant and properly discard but only shear back and toss the plants back into the woods to take root again. The Ash trees, some old growth and 'healthy,' are being cut down (Emerald Ash Borer) rather than treated systemically. And now that the forest floor is getting more sun, a profusion of invasive weedy plants are taking growth.

 

Thanks everyone for being invested in the well being of our community and the Broadlands 'ecosystem'. I'd like to offer a few thoughts regarding the Ash trees. The Emerald Ash Borer (EAB) targets only Ash trees (pheromone driven). By the time the earliest signs of EAB are apparent in Ash trees, it's almost always too late for any sort of a systemic preventative measure. The treatments are very costly for several reasons: chemical cost, licensing, training, specialized equipment, application methods, labor. Additionally, depending on which mode of treatment is used the treatments must be performed every year or every other year. This is a process that likely has to occur for 10 years. Survival rates even with proper consistent treatments are between 50-60%. For argument's sake let's say one wanted to treat 250 specimen ash trees in tree save areas at an average cost of $600 every other year for 10 years (250 x $600 x 5 = $750,000). That's a huge amount of money for a slightly better than average chance of survival. The Association has over the past several years performed some selective treatments on some old growth trees.

I already see young ash trees growing up in the forest as they are getting light that was previously shaded by the larger collective canopies of some of the trees that have succumbed to this pest. Nature has a way of course correcting. This sort of event occurs with different species of plants and trees all over the world at varying times and the outcome though not favorable in our eyes in the short term is that of an ever evolving landscape and urban forest. The Ash trees will return.

Dead trees that are cut down in our common areas are usually left to decompose and return vital biomass to the soil - in turn helping the next generation of plants thrive. After the EAB attacks a host tree, it lays eggs and move on. At this point - the damage is typically irreversible. The larvae feed on the cambium (sappy underside part of the bark) finishing the job and fly off to find another Ash tree. Studies have shown that chipping or shredding the debris has very little effect on the overall insect population. Ash wood cannot be moved outside of the quarantine area. Another benefit to leaving the dead trees in the forest area is that no equipment or excessive foot traffic is required in those areas - minimizing compaction and maintaining healthy soil structures.

Hopefully this info helps without me sounding too much like a professor