It is probably best that you purchase it from a store. American mistletoe (Phoradendron leucacarpum) is a native plant that is parasitic on trees and can severely damage or even kill them over time. It is fairly common in our regional landscape, particularly found on cedar elm (Ulmus crassifolia) and oak (Quercus spp.), which are two of its favorite host trees.
Small greenish flowers give rise to sticky white berries that are spread from tree to tree by birds and arboreal mammals such as squirrels. The berries get lodged into a crevice in a branch and, if conditions are right, they will sprout root-like structures called haustoria. These haustoria grow into the circulatory system of the tree and draw moisture and nutrients from it. Large established colonies of mistletoe can completely engulf the entire canopy of a tree and literally suck the life out of it while also smothering it. Once mistletoe is in place, it cannot be killed without harming the tree; the only way to completely get rid of it is to remove the section of the branch on which it is growing.
It is a shame that a plant that is so beloved is so harmful. Other examples of parasitic plants that grow in our region are the beautiful and somewhat benign Indian paintbrush (Castilleja spp.) that grows with field grasses and herbaceous plants, and dodder (Cuscuta spp.), a very destructive, full-blown parasite which looks like orange silly string and smothers its host plants, rapidly sucking the life out of them like a vegetative vampire!