The mistletoe perched in the treetops in the Southeast is Phoradendron leucarpum, commonly known as American mistletoe. The genus name is derived from the Greek word ‘phor’ (meaning “thief”) and ‘dendron’ (meaning “tree”). This refers to the parasitic nature of mistletoe. Though it has chlorophyll and is capable of photosynthesis, it absorbs water and mineral nutrients from the branches of the host tree. Though it may parasitize many host species, some common ones are oak, beech, poplar, hickory, elm, pecan and maple. Heavy infestations may also be seen in the non-native Bradford pear.
Mistletoe is an evergreen perennial with thick, leathery, oval leaves. It bears small, yellowish flowers, which develop into white berries in fall and winter. The berries are toxic to humans, but are eaten by many birds, such as bluebirds, cedar waxwings and robins. The berries hold a single seed encased in a sticky pulp, and birds spread the seeds in their droppings and by tracking the sticky seeds to adjacent branches.
Seeds that germinate on an appropriate host develop root-like structures called haustoria that grow through the bark and penetrate the tree’s tissues, eventually extending up and down within the branch. Nutrients and water will be drawn from the infested branch, and the branch may be killed beyond the point of attachment of the mistletoe. The tree as a whole will probably survive unless it is diseased or stressed, such as from drought, or if the infestation is unusually heavy.
If you have a mistletoe infestation and are concerned about the health of your tree, the most reliable method of eradication is to prune out infested branches as soon as the mistletoe appears. Pruning the branches back a foot or so below the point of attachment will help eliminate the embedded haustoria. It is especially important to remove mistletoe before it produces seed, and fortunately, it may take several years for a new mistletoe plant to bloom and produce seed. Simply cutting the mistletoe plant out of the tree, and thereby eliminating the seeds, will go a long way toward preventing its spread.
Despite the damage it can cause to landscape trees, not everything about mistletoe is negative. In addition to its legendary magical powers, it serves as the “host” plant for the great purple hairstreak butterfly, meaning that this butterfly’s caterpillars depend on mistletoe for their food. Mistletoe flowers are also an important source of nectar and pollen for bees. And of course, you can always use a sprig to request a kiss or two from a loved one.
Information about Extension Solutions for Homes and Gardens can be found on the University of Georgia Cooperative Extension website at www.caes.uga.edu/extension/cherokee or by contacting the Cherokee County Extension Office at 100 North St., Suite G21 in Canton at (770) 479-0418. The Georgia Extension Master Gardener Program is a volunteer training program offered through county offices of the University of Georgia Cooperative Extension.