noxious plant; harmful plant
Refers to plants that are poisonous, invasive, or otherwise damaging to humans, animals, or ecosystems.
Removal of noxious plants is being promoted in this area.
Please wash your hands thoroughly after touching harmful plants.
毒草 specifically means 'poisonous plant', while 有害植物 is broader and includes plants harmful in other ways (e.g., invasive species, allergenic plants).
雑草 means 'weed' (unwanted plant), but not necessarily harmful; 有害植物 implies actual danger or damage.
Compound of 有害 (harmful) + 植物 (plant). The exact historical derivation is straightforward; the term is a modern technical compound.