Common pokeweed (Phytolacca decandra) is a native plant that can be quite impressive with its towering growth habit and clusters of deep purple berries. According to the University of Illinois Extension, pokeweed is native to much of the United States. As the common name indicates, pokeweed is considered a weed in garden beds and nurseries. Illinois Extension says a single plant can produce 7,000 seeds each year, and those seeds can remain viable for decades. Despite being poisonous, pokeweed was used historically as a food, medicine, and dye.