Hyunsuh Kim

How Japanese Knotweed Came to Europe

A Mutant Ninja Plant in Leiden

Japanese knotweed, or Fallopia japonica— the most invasive plant in Europe. We now understand that water networks such as canals and climate change accelerate the propagation of Japanese knotweed via its rhizomes that get distributed through flowing water, and that the Dutch have unknowingly helped this process all along. However, there is another, even more fundamental reason to why the Netherlands was a causal factor in bringing the plant to Europe, leading it to gain the notoriety it has today. In proposing the Japanese knotweed as the Dutch national flower, we take a closer look at how the story began.

Vergroot

Dutch personnel and Japanese women watching an incoming towed Dutch sailing ship at Dejima - Painting showing  Philipp Franz von Siebold   with a telescope ( teresukoppu ), Dutch personnel and Siebolds Japanese wife Kusumoto Otaki with their baby-daughter   Kusumoto Ine   watching an incoming Dutch sailing ship at Dejima. The ship is towed by many stringed rowing boats. c.1811   - 1842, years of Kawahara Keiga's employment for Dejima.    Image taken from  MIT Visualizing Cultures .

"Plants are as diverse as people. Some are polite, attractive guests you invite into your domain; others are nosy pests who creep in uninvited and take root," claims the webpage of Chicago Botanic Garden ("Plant Profiles"). But how about a plant that enters as a prized visitor only to be despised afterwards? Can we still draw the same analogy to human guests?

 

From the Low Lands to the Shogun, With Love

On April 19, 1600, Liefde ("Love") arrived on the shores of Sashifu. It was the only one out of the five ships from Rotterdam that reached Japan. It was also the first Dutch one to do so. Among the surviving crew members were English William Adams and Dutch Erasmus and Jan Joosten van Lodensteyn, who offered their share of knowledge of firearms, shipbuilding and navigation.

Sixty years ago when the Portuguese, the first Europeans to enter Japan, had brought with them assembly instructions for rifles, chaos broke in a country where previous battles between clans had been fought at best with swords. The rifles that were given to the soldiers of daimyō Oda Nobunaga's triggered the so-called "unification" of Japan, and Nobunaga's successor Toyotomi Hideyoshi later extended these endeavors to invading Korea.

And here we were, in the time of Tokugawa Ieyasu who consolidated the control over the shogunate once and for all. Love from the Netherlands reached the shogun's heart. The Dutch demonstrated themselves as quite enticing guests. 

 

The Window of Dejima

Philip Franz von Siebold was one of the most influential "Dutch" visitors. Actually a German, but with an avidness for exploration, he applied for the position as military physician in the Netherlands to travel to the Dutch colonies. A few months since staying in the Dutch East Indies, he was appointed as resident physician and scientist in Dejima in 1823.

The artificial island also had its unique backstory. Previously, the Japanese had embraced many foreign religious influences, such as Buddhism, that not only coexisted alongside indigenous Shintoism, but fused with it to become its own unique form of Japanese Buddhism. But Catholicism as was preached by the Portuguese missionaries, with its monotheistic, exclusivist message, did not sit well with Ieyasu who was wary against all forms of singular power. In 1614 he banned the religion and banished the proponents into an island specially built for them: Dejima. Twenty-three years later during the Shimabara rebellion, the Dutch secured their standing in the eyes of the shogun by fighting with him, where 37,000 Christians, Japanese included, were executed.

"Rain on the Portuguese means drizzles on the Dutch", said the Dutchmen, trying to convince the suspicious shogun that they would be a more loyal and useful replacement of the Portuguese after Shimabara ("Dutch-Japanese Relations"). Even so, the shogun sought to restrict the freedom of the Dutch, and finally found an excuse to expel them to Dejima when one of their merchants engraved 'Anno 1640' on a newly-built warehouse following the European Christian custom ("Dutch-Japanese Relations"). Nevertheless, what was intended as a prison surrounded by water quickly turned the Netherlands into an exclusive window to the rest of Europe for Japan, and the Dutch in this small trading post truly prospered. Philip Franz von Siebold himself introduced Western science and medicine to many Japanese scholars and in turn learned much about the botany and the culture of Japan. 

 

Banished

But plant specimens were not the only collection that Siebold kept. During his court journey to Edo, Siebold received and kept a series of maps of Japan and Korea, an act that was strictly forbidden by the shogun. When he was found out in 1829, the shogun accused him as being a Russian spy and evicted him. Many of Siebold's friends and students in Japan paid for their relationship with the botanist with their lives.

Back in Leiden, torn away from his Japanese wife and daughter who were forbidden to leave the country, yet with much still left to save from his previous life, Siebold proceeded to retrieve his immense collection of plants and animals from Japan that he had sent to his former residence in Batavia. One of the plants that Siebold brought was Fallopia japonica, or Japanese knotweed. Resembling bamboo with an exotic tinge of violet throughout the green stalk, the plant soon became a staple in the gardens throughout Western Europe. Who would have known that only a century later, house owners would mourn not being able to mortgage their properties due to finding the plant their backyard.

 

The Past is the Present

But is it really possible for a plant that is merely one of a myriad species coexisting in harmony in its native habitat to be so invasive in another land? As recent studies have found, while most of the knotweed in Japan are tetraploids, most in Europe are octaploids — containing 8 sets of chromosomes. Such genetic characteristic has been found to correlate with less phytophagous predators, larger size and all in all a stronger impact on the surrounding ecosystem (Maurel et al.). It has further been demonstrated that in the UK, all the knotweed plants are genetically identical (“Japanese Knotweed Morphology”), and considering that all recorded knotweed plants in Europe are female, they too must be clones grown from one another's rhizomes (Siebold). Should it be one of the most ironic turns of horticultural history, the single knotweed plant that Philip von Siebold brought to Leiden in August, 1850, happened to be a mutant particularly apt to becoming an invasive and suffering the same fate as did Siebold himself.

The clash between the two invasive giants on the shores of Sashifu forced upon their people and others many unprecedented changes. Leaps in economic development, cultural exchange, shattering of the old world and rebuilding of the new world sprung about. At the same time, they left many eternally scarred. After centuries of oppression by the Portuguese and the Dutch, Indonesia would once more be occupied by the Japanese. Siebold and Kusomoto Taki's two-year-old daughter, Kusomoto Ine, who grew up knowing her father only from the finance that he sent across the world, would become the first female Japanese doctor educated in Western medicine. The knowledge passed on from her would both save and kill millions of people a century later. And here in the Netherlands, shocked by the discovery of the much loathed plant in the cracks of one's porch, one hastily tears it out lest it engulfs the whole yard. But the plant did not just come about one day. In fact, for every year that it is pulled out, the remnants of its deepest roots give offshoots the following year. The roots of Japanese knotweed penetrate even the deepest and most negligible nooks and crannies of our streets, and it is only us who, in our oblivion, are surprised again and again upon seeing it rise above the surface. 

 

References

"Dutch-Japanese Relations.". Kingdom of the Netherlands. https://www.netherlandsandyou.nl/your-country-and-the-netherlands/japan/and-the-netherlands/dutch-japanese-relations

“Japanese Knotweed Morphology”. Department of Genetics and Genome Biology. University of Leicester. https://www2.le.ac.uk/departments/genetics/people/bailey/res/f-japonica

Maurel, Noëlie, Masaaki Fujiyoshi, Audrey Muratet, Emmanuelle Porcher, Eric Motard, Olivier Gargominy, and Nathalie Machon. "Biogeographic Comparisons of Herbivore Attack, Growth and Impact of Japanese Knotweed between Japan and France." Journal of Ecology 101(1). (2013): 118-27. http://www.jstor.org/stable/23354672.

"Plant Profiles." Chicago Botanic Garden. https://www.chicagobotanic.org/plantinfo/pp/k

Siebold, Z. “Polygonum cuspidatum”. Discover Life. https://www.discoverlife.org/mp/20q?search=polygonum+cuspidatum&burl=abtadvisors.net/__media__/js/netsoltrademark.php?d=adult-bay.info/category/punjabi-jija-and-saali-1.html&flags=col1:&res=640