Weeds

right|thumb|Weeds growing in the cracks of a concrete staircase (Epilobium roseum, [[Chelidonium majus, Oxalis corniculata, Plantago major)]]

species of plant

efforts to stop or reduce the growth of weeds

species of plant

weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock

invasive plant with positive effects