Reynoutria
The reynoutria form a very small genus of large, flowering plants in the buckwheat (sometimes called knotweed) family. A few species within this genus are utilized by beekeepers for their pollen production. The genus on the whole, however, is more famous for hosting several invasives, most notable among these being Japanese Knotweed (R. japonica). Japanese Knotweed, now found in temperate regions around the world, is considered one of the most aggressive and harmful invasive plant species on the planet.