During our Japan Rail Pass travels in Hokkaido last month, we encountered not just hordes of Chinese tourists (mostly from Taiwan) inside the trains, but also hordes of two kinds of large, green, weedy plants in the scenery that passed by our train windows. Wooded areas were often full of plants we recognized from our past travels as fuki 'butterbur', while more open areas were often infested with what seemed to be a giant, atomic mutant variety of carrot or Queen Anne's lace. We didn't find out what the latter was until we saw a sign identifying it at Cape Nosappu, at Hokkaido's (and Japan's) easternmost point.
Fuki (フキ, also written 蕗、苳、款冬、菜蕗) 'giant butterbur, bog rhubarb'– Petasites japonicus is quite edible after removing some of its astringency. It makes a variety of side dishes to go with rice in both Japan and Korea. (However, too much of it eaten over long periods might damage the liver.) We had encountered it in 2012 at Hikone Castle, where a smaller variety was labeled tsuwabuki, and also at Akita Castle grounds, where we also found butterbur designs on a manhole cover.
Shishiudo (シシウド, also called アンゼリカ anzerika) 'angelica' – Angelica is indeed a genus within the family Apiaceae (or Umbelliferae), which includes carrots, Queen Anne's lace, and many other plants, so my impressions of its taxonomic status were at least in the ballpark.
However, the Japanese generic name suggests that Angelica is a type of udo 'Japanese spikenard, mountain asparagas' (Aralia cordata), in the closely related Araliaceae family, which includes ivy. Indeed, before I found out its name, I thought of it as udo no taiboku 'great tree of udo' (implying something useless, of large size but no strength, like 'all hat, no cattle' in American, or at least Texan, English).
Two local species were identified on the sign at Cape Nosappu. Both common names are prefixed with ezo 'Yezo (the old name for Hokkaido)': エゾニュウ ezonyuu (Angelica ursina); and エゾノロイグサ ezo no yoroigusa (A. sachalinensis var. sachalinensis)
As the Japanese name of the latter suggests, both species seem closely related to the yoroigusa (Angelica dahurica) that grows elsewhere. According to Wikipedia, Angelica dahurica is a wildly grown species of angelica native to Siberia, Russia Far East, Mongolia, Northeastern China, Japan, Korea, and Taiwan. It tends to grow near river banks, along streams and among rocky shrubs. The root of the plant is widely used for its medicinal properties and is known to contain furanocoumarins and angelicotoxin. It is also commonly known as Chinese Angelica, Garden Angelica, Root of the Holy Ghost, and Wild Angelica, as well as its Chinese name, Bai Zhi (白芷).