Personal Note: On the Horror of Invasive Plants and Others

In Michigan we have had an excruciatingly slow and cold spring so far, but with recent rain and kinder temperatures there’s been a long awaited explosion of diverse vegetation—both desirable and undesirable.  I have been spending over an hour each night, digging, weeding and deadheading until the street lights come on.  It’s been mostly pleasant work, fulfilling my need for physical labor after a hectic day of meetings and tapping away at the computer.

A year or so ago my wife and I made the fateful mistake of mulching our gardens heavily with hay instead of straw.  Like many naïve gardeners, we assumed that the terms were synonymous, that a bale of hay is equivalent to a bale of straw.  To the untrained eye, they appear to be the same material.  But straw is cleaner, mostly free of seed heads, while hay contains millions of stowaways, and generally consists of entire plants of various species, dried and bundled up.  The dire consequence of applying hay to the garden is visible in the following years.  It is too late for us; you can still save yourself and your yard.

Our generous application of hay in nearly every corner of our yard resulted in a spectacular number of new weed species being introduced into our gardens.  The immigrants are botanically interesting, at least for a few moments, but are overwhelming in their numbers. Most appear to be highly invasive.  The worst are various grass species that grow rapidly and spread aggressively by way of underground runners.  There are also diverse clovers and mustard-like forbs that are difficult to uproot once established. 

This challenge to the integrity of our gardens is in addition to our historic struggle to control and assimilate certain problematic minorities of plants: Vetch, Adenophora, Bishop’s Weed, Bugleweed and some of the more aggressive Sedum species.  These are plants that we intentionally brought to our gardens long ago to serve various specific purposes, but now insist on popping up everywhere in the yard, even in the better cultivated areas where the more desirable flowers reside.

Usually I am enthusiastic about plant diversity.  With a greater the number of different species, the yard is more attractive to interesting birds, insects and other creatures, and overall, the collection of gardens and patches of lawn seems healthier and more resilient during the late summer drought.  But now our gardens—and our cities—are a chaos of multiple species and cultures.  Part of me wants to restore order and homogeneity, and soon. 

Perhaps this motivation is instinctual in gardeners, landscapers and property owners.  I want to return the gardens to their original pristine state, before the onslaught of the invasive plants.  I share the enthusiasm for eco-fascism that drives the Natural Area Preservation movement, the folks who relentlessly hunt down invading species—the much maligned buckthorn, honey suckle and garlic mustard—hacking and ripping them out of the ground to create Lebensraum for our precious native plants.  It is a kind of xenophobia translated and transplanted into the garden and landscape.  But most gardeners and nature preservationists forget that in a given plot of land, all plants were immigrants once.

Nevertheless, I told my wife that one of my goals this year was to eradicate certain species from the yard forever, in particular Lady Bells (Adenophora stricta), Spearmint (Mentha spicata), and Bishop’s Weed (Aegopodium podagraria).  She gave me a sad, knowing look, but I was undaunted.  We must persevere in our cause.  We must.

Over the years I have had some success at oppressing the dandelions and vetch, diligently removing individual outbreaks I’ve discovered while on reconnaissance in the yard.  While I cannot claim to have exterminated them entirely, I have relegated them to various ghettoes in the yard:  the tiny patch where the wheelbarrow leans against the house, the narrow strip behind the compost bins, the stony alley along the fence.

But while I was accomplishing this important responsibility, masses of bugleweed emigrated from neighboring lawns, creeping across the property lines and overwhelming sections of our back yard.  Our neighbor on the right, an ancient veteran of World War II, no longer has the strength or ground forces to police his own borders, and so the ivy, spurge and crabgrass readily cross back and forth across our western frontier. 

Even more problematic, with respect to horticultural security, are our neighbors to the east.  Their policies toward immigrant species are much more liberal, (that is, lax or nonexistent), allowing some of our vegetable bad actors to flourish in pockets just on the other side, creating havoc in the landscape along that treacherous line.

Then there is our neighbor to the north, with whom we have had a simmering border dispute for decades.  (See also Personal Note: Attack of the Tingids.)  They have allowed, (intentionally?) their ivy groundcover—which is seeking the comparatively sunnier regions of our backyard—to spread from their zone into ours, establishing new and virulent colonies.  Though we have no direct proof, we suspect them of clandestinely funding this vegetable growth with secret applications of an organic fertilizer, which of course is difficult for authorities to trace.

So we are horticulturally besieged by marauding invasive species, approaching from three out of the four points of the compass.  The solution cannot simply be “build a wall” as some have advocated.  Many weed species can easily send their airborne seeds over the top of it, or tunnel beneath such a structure with their extensive root systems.  Paving the entire yard, turning it into a parking lot or an extension of the road, would likely be effective for only a decade at most.  And some would undoubtedly complain about the environmental impact of such a project.

Though grim business, it may be that constant struggle and vigilance is the only solution to the challenge of managing the encroachment of invasive plant species.  Preserving the identity and coherence of the garden, its glorious historical past, its bright colorful future, requires it.  The alternative is green chaos: a slow steady strangulation of our instinctual efforts to ensure order, control, productivity, and peace for our posterity—the entanglement of the good, the true, the beautiful—the American way—in the tendrils of an unruly and disrespectful Nature.