In the Language of Flowers Mistoe symbolized "Surmounting all Difficulties" A Ball of Mistletoe is often hung over doorways, and there is a tradition that people Kiss when they are underneath the Mistletoe. Mistletoe has a long history as a symbol of Life and Luck, among other things the Mistletoe is actually a Parasite plant, which means it grows on trees and can damage them. The berries, leaves and stem of Mistletoe are poisonous.