Also known as poke root and pokeberry, pokeweed is a perennial that can grow six to eight feet tall. It’s festooned with white clusters of flowersthat give way to shiny berries that attract birds. Every part of this plant is harmful, especially the roots, and contact can cause anything from vomiting to internal bleeding. Even worse, pokeweed is invasive and difficult to eradicate. For the best chance of success, take swift action if you notice the weed on your property.