Lessons from an Overgrown Garden
Lessons from an Overgrown Garden
by Angie Littlefield
I invited into my garden the aggressors that now run amok. Long gone are the days of gentle irises and features of perennials like penstemon and sea lavender. My garden is overrun with a rougher sort. These plants are “bigger, meaner, and pushier than anything else in the garden. They’re frequently the first to show up in the spring. They compete relentlessly for soil nutrients, moisture and growing space . . . And they’ll fight back if you try to subdue them.” (Jerry Schleicher. “The Worst Invasive Plants and Garden Weeds,” Grit. 18 Apr. 2011)
The ferns I introduced from a neighboring ravine now march boldly from the shade they were supposed to prefer into the sunlit center of the garden. They are taking no prisoners as they overwhelm hellebore and giant Solomon’s seal, plants with which they once co-existed in the borderland between sun and shade.
The Chinese lanterns are another problem. I placed them in my side-yard because I needed a plucky plant under established trees. Within a year or two, the brassy lanterns colonized the entire area. Then they had the chutzpah to migrate around the corner into my back garden. (I suspect with the help of a bird accomplice.) From a single position in the backyard, the lanterns conducted warfare with their rhizomes, which they spread under the ground to weave an invisible death blanket.
David Beaulieu wrote in his blog, “There is no magic bullet to use to control and/or kill Chinese lanterns. The best advice we can give is to employ a variety of methods (underground barriers, herbicide sprays, digging, smothering tarps) . . .” (David Beaulieu. “How to Control or Get Rid of Chinese Lanterns.” The Spruce. 27 Aug. 2018). In other words, War!
Other plants I bought should have come with warning labels. Never mind sun or shade stickers, blaze the bullies with yellow hazard signs to denote spreader and super-spreader. Our periwinkle escaped behind our house and was last seen headed uphill to the east. The lamium snuck through the chain link fence into the ravine. Our so-called obedient plant ceased to have manners, and we struggle to keep the bishop’s weed and ivy at bay with a lawn mower.
And these were the plants I invited in. When I was younger, I tried to combat the intrusive tree-like weeds called horsetail. They sprouted unbidden each spring with sci-fi-like spore towers. I gave up when I discovered the plant’s extensive root system lurks below the surface at the depth of two spades.
I read up on the species and found that horsetail peaked 350-million-plus years ago when it grew to ninety feet high. It is the source of most of our current coal supplies. Mexico, Central, and South America still have horsetails that reach heights between sixteen and twenty-four feet. So, who was I to tamper with a species that existed when dinosaurs roamed the Earth? Besides, my horsetail has bigger worries. Other weeds are gunning for its share of sunlight, among them goldenrod.
Two types of goldenrod appeared on our eastern perimeter a few years back. These aggressive spreaders are currently duking it out with the Chinese lanterns and horsetails at the rear of the yard. I’m not sure anymore what used to grow where this battle is underway, but I have vague memories of coreopsis and gallardia. 
There is, however, a “goldenrod” lining to this invasion. These plants are native, drought-resistant, make an herbal tea that is good for reducing inflammation, and attract bees, butterflies, and other pollinators. So: “Let it be, let it be . . .”
I cannot find the same Zen in the scourge of dog-strangling vine, or DSV. I have seen it form dense mats that smother native plants, climb telephone poles and trees, and cover hillsides. Each plant produces up to 2,400 seeds per eleven square feet, and it also spreads through rhizomes. Pull it, and it multiplies like the broom of the sorcerer’s apprentice. It’s a replication nightmare.
Naomi Cappuccino, associate professor of biology at Carleton University in Ottawa found that DSV does not play fair. Its roots produce chemicals that alter the soil and slow down the root development of competing plants. To boot, monarch butterflies sometimes mistakenly lay their eggs on DSV, and their larvae cannot survive on its toxic leaves. Its reach is extensive in Canada and the US—and, well yes, it’s in my backyard. I caught DSVs trying to wrap themselves around my tree peony.
DSV is native to Russia and the Ukraine, where it is not invasive. The hypena opulenta caterpillar keeps it under control there. In North America, DSV has no insect or livestock attackers. A research paper published by the Agricultural Research Service of the United States Department of Agriculture reviewed the experimental impact of the hypena opulenta caterpillar on DSV (called swallow wort in the article). It provided highly technical but promising news based on a literature review, lab study, and some controlled caterpillar releases. (Lindsey R. Milbrath and Jeromy Biazzo. 2016. “Impact of the defoliating moth Hypena opulenta on invasive swallow-worts . . . under different light environments.” Biological Control 97: 1–12).
I am in favor of controlling DSV, to be sure, but I am reminded of the Emerald Lagoon hike I took at the tip of South America in 2018. I had to downplay that I was Canadian because of the headshaking and cursing about Canadian beavers. It turns out that fifty beavers were imported in 1946 to the Lake Fagnano area in southern Chile and Argentina to establish a fur industry. The fur enterprise was abandoned, and the beaver were either released or escaped. Without any predators, that fecund fifty generated between 70,000 to 110,000 offspring today. Argentina and Chile have been forced to create an expensive beaver eradication program to deal with the damage Canadian beavers have visited upon their habitats.
Does the future hold a hypena opulenta caterpillar eradication program in North America? My overgrown garden bears life lessons.
Photo by Annie Spratt (New Forest National Park, UK)
