Mistletoe: Love it or leave it

By By Steve Strong / area horticulture extension agent
Dec. 18, 2002
Mistletoe is as much a part of Christmas tradition as tinsel-wrapped trees, poinsettias and carolers who go door to door.
However, song lyrics are likely to change this winter to "Whoa, Whoa, Whoa the Mistletoe" as homeowners' favorite shade trees again drop their leaves to reveal their relentless attacker.
Mistletoe is described as a parasite, and is one of a few such plants that also contain the green pigment chlorophyll similar to other higher plants.
Surviving as an evergreen invader in our area, mistletoe is hidden during most of the growing season in the leafy canopies of various tree species like water, willow, and red oaks.
Pecan, hickory, hackberry, and green ash are also commonly victims of mistletoe infestation, and once it appears it usually remains until the death of the tree. Mistletoe is not a direct cause of death through disease infection, but instead creates extra stress on the host plant by draining valuable water and nutrients vital to healthy growth.
Think of mistletoe as the horticultural version of a vampire bat or blood-sucking leech, able to inject its root-like "haustoria" through the protective bark layer and tie itself directly into a tree's circulatory system.
Mistletoe becomes an integral part of the growing tree, thriving as the tree thrives, and able to produce fertile fruit seen as clusters of white-green berries during the winter months.
Birds primarily consume the fruit and then spread the seeds from tree to tree, requiring only a small crack in the bark and a little moisture to sprout new plants. Because mistletoe seeds are covered with a thick, gummy pulp, they stick to the bark of their new victims just like glue.
Once the mistletoe seedlings have connected themselves to the tree's vascular system, they become difficult to control. Any herbicide that might effectively kill the mistletoe (glyphosate or Roundup) could also be absorbed internally and cause serious injury to the tree.
For this reason, the best recommended control is the removal of infected branches as soon as new mistletoe sprouts become visible. Pruning cuts should be made at least 1 foot below the infestation to outrun the growth of the mistletoe's embedded root-like haustoria.
Cutting back to the main trunk to remove severely infested branches may be necessary, and older weakened trees that serve as a seed source for more mistletoe may be removed entirely.
If branch removal is not an option, try pruning the mistletoe all the way back to the infested branch, and wrapping the area with several layers of black plastic sheeting to exclude sunlight.
It may take several years for this drastic measure of wrapping and taping to work, and it will probably create more of an eyesore than the mistletoe itself. Mistletoe can attack healthy trees, but seems to favor specimens that are already under stress thus, the best strategy is prevention by keeping the trees as healthy as possible with proper watering and fertilizing.
Understand that not everyone in the country hates mistletoe as deeply as Mississippi gardeners, and in fact, Oklahoma even made the parasite its state flower (guess folks out there are thankful to have anything growing green in the wintertime).
It still makes a wonderful holiday garnish above household doorways, providing lovers both young and old with an easy excuse to share affection with one another.
Shooting mistletoe out of trees is also a great way to get in some holiday target practice, and stimulate a Christmas kissing frenzy at the same time.
Just be sure that the significant other you get caught with underneath the mistletoe is a willing victim, unlike the unsuspecting oak that has no choice but to accept the fatal embrace of its obsessive and parasitic lover.