Japanese knotweed

BBCのWebサイトを見ていたら興味深い記事がありました。以下はその冒頭箇所からの引用です。

The beer I'm sipping has a sharp, tart flavour, similar to rhubarb. But fruit isn't the main ingredient. The cold brew is made from the UK's most damaging plant: Japanese knotweed.

Introduced in the UK as a highly prized ornamental plant in the mid-19th Century, Japanese knotweed is widely considered one of the world's most intractable invasive species. With its creeping roots, the weed can smother gardens and parks and is the scourge of homeowners.

But at Silo, the zero-waste restaurant in east London where I'm dining, Japanese knotweed is a firm favourite. Head chef Doug McMaster has been cooking with the weed for years. "It's an amazing ingredient," he says. "It's incredibly versatile; it can be grilled, it can be cooked, it can be turned into beer, fermented and pickled.

日本の植物で "invasive plant" として有名なのは葛で、英語でも "Kuzu" として良く知られていますが、上記の "Japanese knotweed" とはどんな植物でしょうか？

・Wiktionary: A large, herbaceous perennial plant, Fallopia japonica, native to Asia; it is a highly invasive colonizer outside of its native territory.: We got into this because we were looking at invasive species at the roadside, such as Japanese knotweed. A lot of rail embankments have been solidified by knotweed because the roots are so strong.

Wikipediaには "Japanese knotweed" をredirectした "Reynoutria japonica" の項に詳しい説明があり、 "Japanese knotweed" の和名について次の記述があります。

It grows widely throughout Japan and is foraged as a wild edible vegetable (sansai), though not in sufficient quantities to be included in statistics. They are called by such regional names as tonkiba (Yamagata), itazuiko (Nagano, Mie), itazura (Gifu, Toyama, Nara, Wakayama, Kagawa), gonpachi (Shizuoka, Nara, Mie, Wakayama), sashi (Akita, Yamagata), jajappo (Shimane, Tottori, Okayama), sukanpo (many areas).

私はどれも全く知りませんが、スカンポは唱歌に「土手のスカンポ」とあったことだけ覚えています。スカンポを日本語のWikipediaで調べると、イタドリとスイバの別名とあり、二つの別の植物を指しています。イタドリとスイバのそれぞれの項を見ると、イタドリの学名は Fallopia japonicaで、スイバの学名はRumex acetosa L.と書かれていて、イタドリは世界の侵略的外来種ワースト100 (IUCN, 2000) 選定種の1つでもあるとの記述もあるので、BBCの記事の "Japanese knotweed" はイタドリを指していると思われます。