The Great Replacement

 

Stiltgrass in adjacent King George County. Photo by R. Singh

Japanese stiltgrass is everywhere. This modest, rather pretty plant with lanceolate leaves emblematizes Potomac Creek’s intimacy with the rest of the world -- an intimacy so quiet and obvious it hides in plain sight. For all our hopes, brainpower, and planning, stiltgrass shows that we haven’t the faintest idea what the Creek will be like in a hundred years. 

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One usually finds microstegium vimineum, commonly known as Japanese stiltgrass, where paths are worn in the forest surrounding Potomac Creek, or the ground has been disturbed by deer or scouring floods. Stiltgrass may be the most damaging invasive plant species in the country. A pretty plant with silver-striped lanceolate leaves, it easily outcompetes forest floor rivals in shady, humid areas. It can spread to create thickly-matted, pasture-like areas that block the natural development of an understory. Plant diversity and wildlife habitat suffer. The Forest Service lists stiltgrass as a Category 1 invasive plant – the worst in terms of displacing natives – and ranks it the invasive plant of greatest concern among researchers and land managers in the eastern US. 

In other words, if anti-foreigner paranoia propels you towards QAnon and fear of a “great replacement,” then stiltgrass is your botanical foe.  Except it’s not a conspiracy. Stiltgrass is more like what the CIA calls “blowback”: the unintended, harmful result of one’s own actions.

How did this unwelcome Asian native come to America? As with many migrants, the answers lie in conflict and opportunity. 

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The story of stiltgrass is a small tale lost within the dramatic push and pull of nineteenth century geopolitics. National interest in the Pacific grew after the United States successfully annexed California in 1848. According to the official history of the State Department, the resulting US policy was an extension of the doctrine of Manifest Destiny that drove settlers west across the American continent. Now, Americans wanted more trade and influence with China and Japan, including missionaries, and secure ports and coaling stations for their whalers, merchants, and naval vessels. The isolationist Tokugawa shogunate in Japan resisted American designs. But strategically Japan was the right place to be. To stiffen US diplomacy, President Millard Filmore sent across the ocean a squadron of US Navy ships led by Commodore Matthew Perry. Perry’s armed ships sailed into forbidden Tokyo Bay in 1853. Within a short time, America and Japan were literally in business.  

Matthew Perry (Wikipedia)

This is one of many historical moments where global politics and biogeography – the branch of biology that studies the geographic distribution of plants – come together. Commodore Perry’s coerced opening of Japan quickly led to botanical exchanges. The late botanist Les Mehrhoff picks up the story in a lecture delivered to the 2010 “Stiltgrass Summit” (such events exist). But it’s very unlikely that anyone planned for stiltgrass to take root across the world’s largest ocean.  

Instead, that achievement took something as fickle as a fashion trend. Europeans had long coveted East Asian ceramics. The Perry mission and Japan’s subsequent participation in the 1876 Centennial Exhibition in Philadelphia induced yet another “Japan Craze,” this time in the United States. Americans of the rapidly industrializing late nineteenth century came to see Japanese and Asian porcelain as symbolic of a less harried life, where artisanship and harmony with nature still mattered. The export market for Japanese art boomed. And merchants used readily available stiltgrass to package the goods for safe transport.

The first time anyone noticed Japanese stiltgrass growing in the United States was in 1919. George G. Ainslie, an entomologist studying borers (insects that bore into plants) found the grass growing on a creek bank in Knoxville, Tennessee. Unable to identify it, he sent a sample to the Smithsonian in Washington DC. 

The trouble with stiltgrass isn’t just its destructive effects on native ecology, but its remarkable fecundity. As an annual plant, it flowers then sets seed in late summer and early autumn. Each stiltgrass may produce as many as one thousand seeds which can remain viable for several years. In fact, once you’ve walked through a patch of stiltgrass it’s probably harder not to spread the seeds than it is to spread them. The seeds can be disseminated in nearly infinite ways: wildlife, rains and floods, and people – think mowers, hikers, backpacks, tents, car tires, shoelaces, and so on. Stiltgrass was first recorded in Virginia in 1931. It continues to colonize new states, especially those of the south and east. Stiltgrass was confirmed in Rhode Island in 2005, and Wisconsin in 2020. For all anyone knows, it rode in on the fur of a black coyote.

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The story of stiltgrass is a lesson in humility. 

We were the Leopards, the Lions;

those who'll take our place will be little jackals, hyenas;

and the whole lot of us, Leopards, jackals, and sheep,

we'll all go on thinking ourselves the salt of the earth.

    Giuseppe Di Lampedusa, The Leopard