Sosnowsky's hogweed is very bad plant (it remebers something ugly like situations in "The Day of the Triffids")(as is radiation, besides), but radiation and poisonous plants create special places where there aren't many people, traders and trade. In the future, more and more people will migrate specialy into radioactive places overgrown with Sosnowsky's hogweeds more away from this society, inaccessible to modern people (buying and selling plastic statues of Shakyamuni Buddha to each other). There they would think 'bout the eternality, and look at the sky. Tsingy forest became such a place for endangered lemurs of Madagascar, and for wild deer (mostly exterminated) the Chernobyl district, and for the out-of-that-world stalker from Tarkovsky's film of the same name, the forbidden zone...