Being from the southern US, I am all too familiar with a sight you often see traveling through Dixie – places where a single type of vegetation forms a thick, tangled carpet of green that covers not only acres and acres of land but also living trees, abandoned cars, derelict houses, you name it, anything that doesn’t move. I’m talking, of course, about kudzu.
Kudzu is a fast-growing vine native to southern Japan and parts of China and Korea. It was introduced to the US over a century ago and was adopted as a cure for soil erosion because it quickly takes root in land denuded of other vegetation. In that role, it succeeded. But it didn’t stop there. It just kept growing.
|Kudzu overtaking trees near Atlanta.|
It’s not an easy plant to kill, or harvest (supposedly, it does have some economic uses.) At least goats will eat it. I recall that in my hometown in Georgia, someone used these four-legged mowing machines to clear a kudzu-covered hillside. Usually, though, it seems kudzu resists all efforts to eradicate it. Every year, it envelops 150,000 additional acres (61,000 hectares) of US landscape, leading to the joke that it’s the “vine that ate the South”.
Exotic species, like kudzu, which thrive a little too well in new habitats pose huge problems, not only for humans, but also especially for native species they displace or feed on.
Currently, US biologists are dealing with the spread of Africanized bees (“killer bees”) in the southeast, an extremely aggressive fish, Asian carp, in the Mississippi watershed (potentially invading the Great Lakes), and even a proliferation of Burmese pythons (yikes!) in southern Florida marshlands, where they are decimating local wildlife.
Finland, too, has its share of exotic species. (However, with the Finnish winters, there’s no threat that Burmese pythons will ever get a foothold here.) Some of these invading species would hardly be even considered a nuisance, let alone noxious.
This summer, on a drive to Savo in eastern Finland we noticed that the exotic plant Lupinus polyphyllus was growing more abundantly along the roadside and spreading further north than ever before. This foreign species is otherwise known as “garden lupine”, a very attractive “wildflower” I seem to recall from road trips in Wyoming and Colorado. It doesn’t belong in Finland, though as invasive weeds go, it’s certainly not the most objectionable.
|Lupines in Alaska.|
That’s not true for another weed I came to know this summer. Giant Hogweed (Heracleum genus) lives up to its disagreeable name. A native of the Caucasus Mountains, it grows up to four meters or more in height in Finland and spreads voraciously, easily crowding out native plants. It’s also bad news for humans. Contact with this toxic plant causes blisters on the skin that can result in permanent scars. A tiny amount of its sap in the eyes can cause blindness. It is one nasty, nasty member of the plant kingdom.
A colony of Giant Hogweed has established itself in an abandoned field downstream from my in-laws’ summer place in Savo. A local farmer has tried to destroy the particular outbreak of this weed from hell, but its growth seems hardly abated.
Giant Hogweed has been spreading to eastern Finland in recent years from Russia, where the offensive weed has thrived for decades. In fact, it was once actively cultivated there.
The story goes that Stalin, a native of Soviet Georgia, like Giant Hogweed itself, had seen in the monstrous weed great potential as a source of feed for collectivist cattle. It was to be the Soviet answer to a much better silage crop that wasn’t well suited to Mother Russia, but grows so abundantly in the imperialist fields of Iowa, namely maize (corn).
|Giant Hogweed encroaching on an abandoned sauna in Savo.|
Stalin reportedly decreed that Hogweed was to be introduced to northwest Russia in 1947, and it did produce a lot of plant material for livestock, just as Uncle Joe had hoped. But it also left a foul taste in the milk and meat of the cattle that ate it. That, and the small matter of its extreme toxicity to humans, doomed it as a crop of any use. Unfortunately, its failure as a crop didn’t doom it to oblivion. It only continued to spread, as it does today.
With some irony, Russians have come to call this almost indestructible plant “Stalin’s Revenge”. In light of my southern heritage, I can only think of it as “Stalin’s Kudzu”.