Re-Thinking Invasive Plants

It is early March, the snow has barely melted, the sap’s running and it’s time for my first harvesting expedition. The mustard family has the opening act on the forager’s stage with its supernutritious, cold-hardy, pre-season greens, namely: watercress, wintercress (field mustard), and garlic mustard.

Whenever I harvest garlic mustard, it feels a bit like an act of treason, as if I am supposed to be cursing it, campaigning against it, and ripping it out of the ground rather than enjoying the vinegars, mustards and pestos I’ve come to love. Garlic mustard ranks high on the 10-most-wanted list of invasive plants in Wisconsin as it aggressively moves into our hardwood forests. It emerges long before the first ephemerals of the spring and shades out the woodland plant populations, driving away wildlife and generally ‘messing up the woods’.

Sitting in a patch of tender young garlic mustard sproutlings with my basket in hand, I can’t help but contemplate the phenomenon of invasive species. I’ve read the glossy brochures, studied the wanted posters on interpretive center walls and generally educated myself about the problem as a dutiful citizen. But somehow I always find myself on the fence with this issue, never quite knowing which side I should be standing on. Part of me sympathizes with the losses and costs incurred because of invasive species and with the changing local ecosystems. But another decidedly radical voice in me secretly admires these invaders and I find myself wondering “Can invasive plants serve a purpose in nature or are they truly the scourge we’ve made them out to be?”

It gets a little trickier to define native because plants are not stationary and manage to travel even without the aid of humans. Events like climate changes, animal activity, wildfires, floods and natural succession are constantly changing the biotic landscape. Plants that originated in one corner of the world may have naturalized elsewhere for thousands of years. At what point do they become native? In the US, native plants seem to be pre-Columbian plants, plants that were here before the first white man ever set foot on the continent. Native plants are also loosely defined as plants in natural communities that have co-evolved over time and maintain a degree of homeostasis or balance. Hunter/gatherer cultures didn’t seem to significantly alter native plants communities according to these definitions, therefore native plants could be also described as pre-agricultural.

   It’s interesting to note that we humans tend to perceive the boundary disputes in the plant kingdom as similar to the human story of war and conquest over territory, rather than a co-evolutionary process. Invasive plant literature is replete with war terminology to describe the situation and the tactics needed to control it. Implied in these labels, as well as in the science of invasion biology, is the idea that these seemingly aggressive, threatening tendencies are intrinsic properties of invading species. Richard Manning in his book "Against the Grain" talks about a “coalition of weeds” that moves in wherever agrarian cultures displace hunter/gatherer cultures. These new non-native plants literally follow civilization around. Plantain was called “White Man's Foot" by the Native Americans because it seemed to grow right out of their footprints as they blazed their trails through the wilderness.

    The irony in the war on invasive plants is that agrarian civilization has done more to displace native species than any of the listed invasive plants could ever hope to. Here in America, for example, the flora of the land has been completely reshaped by the advent of the Europeans over the course of a few, short centuries. Forests have become farms, diverse prairies a breadbasket monoculture, deserts into grazing lands, rivers dammed or re-routed, mountains leveled and defaced for ores and minerals, clear-cutting, the list goes on and on and on. One might ask, “Who’s the real invasive species here?”

Claude William Genest of Green Mountian Permaculture Institute writes: The Nobel prize winning "Gaia Theory" teaches us that the earth is like a body : it self-organizes, self-repairs, and self-reproduces. It is a single, self-regulating living system that organizes itself in such a way as to maintain and create the conditions that are suitable for life……..Similarly, invasive plants are also operating in the context of the whole-system. Take a closer look: they are absolutely specialized at cleaning up our mess and repairing degraded soils. Purple loosestrife's historical progression can be traced right up the fouled waters of our man-made canals and its ability to fix nitrogen and mine minerals make it an ideal pioneer species for degraded former wetlands. Eurasian Millefoils' "thousand leaves" give it more surface area with which to capture the nutrients we so ignorantly and abundantly provide and Zebra mussels fix our phosphorous overload like nobody's business……..Living systems evolve towards diversity, complexity and resiliency. Pioneer species including many exotics, "take-over" for what appears to be a long time only in our myopically short life-spans. The pattern in fact is one of "succession" in which one species helps create the conditions for the next. Life creates life, even in death.

It may be no accident that these same weeds that are busily working to restore the land are also some of our most powerful healers. “Noxious weeds” like dandelion, burdock and garlic mustard are nutritional powerhouses that offer themselves to us humans in super-abundance to help us to nourish our depleted bodies, leach environmental toxins, and otherwise help us to cope with our industrialized world. Yet instead of receiving the gifts these plants bring with them, alien species are villanized and portrayed as terrorists, competing with crops, threatening to reclaim fields, re-route waterways, starve the herds, the list goes on.

Most of the charges being leveled at invasive plants have to do with their disruption of human activities and land management practices. . In one brochure I picked up it states that invasive plants “reduce agricultural yields, decrease gathering opportunities, and hinder recreational activities. Eurasian watermilfoil chokes waterways and restricts boat access, while the toxic properties of wild parsnip deter hiking and other land-based activities.” It would seem as though these plants were declaring war on us! From a Gaia perspective these might be considered intelligent strategies for protecting the land, but from a human perspective it is a major threat.

The economic impact is calculated at some 138 billions of dollars per year. These figures factor in the cost of research, conservation projects, labor, crop losses, devaluing of land, and the high price of chemical and other eradication programs. Fortunately, herbicide manufacturers are willing to help shoulder the burden of getting rid of invasives. Monsanto, for example, has been instrumental in the formation of the Exotic Pest Plant Councils.

There are laws in the village against weeds
The law says a weed is wrong and shall be killed.
The weeds say life is a white and lovely thing.
Carl Sandburg

The war on invasive plants is being fought from many fronts and there are very, very few people opposing it or even questioning it. There’s a Global Invasive Species Program, a National Invasive Species Council and large, influential conservation organizations like the Nature Conservancy enlisted in the cause. There are countless private citizen actions on the local level as well.

There are numerous legislative attempts to control alien plants, such as the watercress ban in Connecticut and other local ordinances where landowners can actually be fined for not getting rid of targeted noxious weeds. There is also a proposal to initiate a government-approved White List of plants and close the borders to the free exchange of plants and seeds.

Perhaps the most shocking trend in invasive species warfare is the justification of widespread chemical herbicide application. Many non-targeted lifeforms suffer from this, including the very native species we are allegedly trying to save. This and the use of other eradication techniques such as controlled burns, biocontrol and manual removal projects all alter the environment as much as or more than the presence of the invasive plants.

It seems as though such attempts to manipulate and manage the environment are self-defeating. Nobody really wins. Senior research scientist at Harvard University, Peter Del Tredici , writes, “What’s striking about this so-called restoration process is that it looks an awful lot like gardening, with its ongoing need for planting and weeding. Call it what you will, but anyone who has ever worked in the garden knows that planting and weeding are endless. So the question becomes: Is “landscape restoration” really just gardening dressed up with jargon to simulate ecology, or is it based on scientific theories with testable hypotheses? To put it another way: Can we put the invasive species genie back in the bottle, or are we looking at a future in which nature itself becomes a cultivated entity?” It makes more sense to somehow integrate these invasives and harness their potential rather than to continue to fight a costly and losing battle:

*** Some invasives are edible and could be considered as a sustainable food resource. Wisconsin’s own J.M. Franke, author of the Invasive Speicies Cookbook, claims that “the power of the human alimentary tract to act as the final resting place for non-human life-forms is not to be underestimated. Even formerly abundant species such as the passenger pigeon were rendered extinct at least in part to satisfy the bellies of humans.” I like to fantasize about the day when garlic mustard pesto is a high-dollar, gourmet food item at Whole Foods. Wild Parsnips are one and the same plant as the parsnips we pay several dollars a pound for at the co-op. Autumn Olive berries are a favorite of local foragers.

*** Some invasives offer some very timely medicinal benefits for our industrial age. For example, Japanese Homeysuckle Blossoms have anti-microbial properties proving to be effective against anti-biotic resistant bacteria. Creeping Charlie is being extensively studied for its ability to leach heavy metals out of the body. And who needs factory vitamin supplements with supernutritious plants like garlic mustard growing in abundance?

***Invasive plants offer cover, brushy habitat and food for wildlife, despite claims to the contrary, and some argue that they actually increase biodiversity once the initial outbreak self-regulates and integrates with its new eco-system.

*** “Phytoremediation” is the emerging technology of using plants to extract, degrade, contain or immobilize contaminants in soil, groundwater, or surface water. Many invasives tend to be pollution-tolerant plants that are able to withstand today’s chemical soup and may be perfect candidates for phytoremediation projects, indeed they may already be serving that very purpose without our assistance. At a recent SPROut (Sustainable Plant Research and Outreach) conference, a comment was made about the discussions that “while the native plant supporters tend to classify plants by geographic distribution, either current /invasive or historic/native, the phytoremediation practitioners prefer to classify plants by function, i.e. which plants are good at removing which contaminants from the soil.”

***There is accelerated research being done into biofuel possibilities. Many of the species commonly proposed as biofuel plants share numerous traits in common with invasive plants and there is considerable concern that we will be relasing new invasives into the environment by cultivating them. Why aren’t we looking at invasives with large biomass that are already here such as the infamous kudzu vine? Kudzu could be transfigured into a renewable, sustainable resource and a source of income for many landowners as a biofuel.

I think there needs to be a major paradigm shift in our attitude towards invasive plants. Since simply getting rid of them is obviously not an option, we need to learn to somehow learn to peacefully co-exist with them, harness their potential gifts, and seek to understand their role in our rapidly changing ecosystem from a Gaia perspective. Personally, I choose to believe in nature’s innate ability to self-repair and in the intrinsic good intentions of the plants that appear in the landscape. There is probably a whole lot more going on in this garlic mustard patch than anyone realizes. So when life hands you a patch of garlic mustard, make pesto…….