“The eye sees only what the mind is prepared to comprehend” — Henri Bergson, French philosopher
In the January-February printed edition, the Bay Journal noted that the nonnative hydrilla “has become important in the Bay as a ‘pioneer’ species, colonizing unvegetated areas and making them suitable for native grasses.” People working for the federal government long ago realized that some alien plants, like Hydrilla verticillate, perform better than native plant species to repair degraded environments, which is why many plants now referred to as “invasive” — such as autumn olive (Eleagnus umbellata) — were brought to the United States in the first place. Autumn olive helped with mine reclamation in the 1830s.
Was it a mistake to bring such plants to this country to help fix the destructive impact of humans on the environment? In my opinion, no. With an increasing population, accompanied by development of the land, and with increasingly warmer and droughty conditions due to global climate change, some of the so-called invasive species could be the unintended saviors of our wildlife. But, to see it that way, people need a better understanding of soil science and how the natural world works.
For example, it’s common to see abandoned fields and roadsides in Virginia filled with autumn olive as you drive throughout the state. You could easily believe the dogma that these Asian plants “pushed out” native plants and took their place, but, simply put, you’d be wrong. Without an assessment of prior land use and the soil itself, you can’t possibly come to a reality-based conclusion about why certain plant species grow in these areas.
Generally speaking, both roadsides and unused fields are compacted and nutrient poor. In fields, that’s either because half-ton cows trod over them day after day or because the crops required heavy machinery to “prepare” the soil, sow seeds, and care for and harvest the plants every year. Roadsides are compacted by the heavy machinery used to prepare the roadbed, and they are usually bereft of nutrients because the topsoil has been removed, leaving behind a dense subsoil comparatively devoid of organisms and nutrients.
Therefore, the plants you see as you drive along highways and past neglected farm fields are only the plants capable of growing well in those inhospitable soils. They rehabilitate the soil for the benefit of native plants that require good (that is, crumbly and nutritive) soil in which to grow well. Only after the “pioneers” like hydrilla and autumn olive have done their work can such plants move into these impaired locations.
Native pioneer plant species are few in the Piedmont region of Virginia (where I live), consisting mainly of Eastern redcedar (Juniperus virginiana), Virginia pine (Pinus virginiana), Eastern white pine (Pinus strobus in mountainous and foothill areas), broomsedge (Andropogon virginicus), and, though not actually native to this part of the state, black locust (Robinia pseudoacacia). You will often see these plants joined by autumn olive, a hint that supposedly invasive plants are simply nonnative-pioneer plants, increasing the diversity of plant life and thus animal life in these areas.
Autumn olive shrubs and black locust trees in fields and roadsides share an extremely useful attribute: the ability to fix nitrogen and thus enrich poor soil (a desirable trait of peas and beans that is often employed by gardeners for that reason). Such plants serve as Mother Nature’s nitrogen cooperative, working with bacteria that enrich the soil by adding this vital nutrient — making it less necessary for us to squander limited resources like petroleum in making synthetic fertilizer.
Unfortunately, the predominant narrative nowadays is that everyone must remove supposedly invasive plants that are mistakenly believed to have displaced native plants while not offering their ecological benefits to the environment. It’s a false narrative, but not surprising, given that people are prepared to understand only what their own biases and limited experiences allow. Yet anyone can find out the truth about these plants. It’s not rocket science; you simply need to observe the natural world without preconceived notions and grow these plants on your property.
I’ve observed in my own yard how black knapweed (Centaurea nigra), Japanese honeysuckle (Lonicera japonica), autumn olive and the royal paulownia tree (Paulownia tomentosa, aka empress tree) feed our pollinators with blooms, nourish birds and mammals with fruits, seeds or buds, and even furnish nesting material and/or sites. In years when deer overpopulated the area, they denuded my yard of most native plants, which would have destroyed all habitat if I hadn’t included commonly disparaged invasives in my yard that deer didn’t eat. It’s often overlooked that deer are capable of eradicating native plants, leaving the false impression that the natives have been driven out by nonnatives.
In the severe drought years of 2002 and 2003, I witnessed how native species withered alongside the roads as I drove to Shenandoah National Park to give monthly slide presentations. Meanwhile, alien species continued to flourish despite drought and drying winds.
If you care about wildlife, ignore the siren call of voices who frame the invasive plant “problem” in terms of morality, suggesting it is your “duty” to destroy these plants. They couldn’t be more wrong.
Marlene A. Condon is the author-photographer of The Nature-friendly Garden (Stackpole Books 2006). You can read her blog at InDefenseofNature.blogspot.com.
The views expressed by opinion columnists are not necessarily those of the Bay Journal.
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