noun
noxious plant; harmful plant
Refers to plants that are poisonous, invasive, or otherwise damaging to humans, animals, or ecosystems.
この地域では有害植物の駆除が進められている。
Removal of noxious plants is being promoted in this area.
有害植物に触れた後は手をよく洗ってください。
Please wash your hands thoroughly after touching harmful plants.
Compound of 有害 (harmful) + 植物 (plant). The exact historical derivation is straightforward; the term is a modern technical compound.