Onionweed is a tenacious invasive weed that grows well in poor soil and has established in the Southwest. It can degrade pasture land as it crowds out native grasses and is unpalatable to livestock. A dedicated group of Arizona homeowners working with APHIS Plant Safety and Research staff members removed onionweed
from their landscapes. In 2008, there were 116 sites with no onionweed plants found and numerous others with visible efforts at control of this invasive plant.