If you’re searching for a sprig of mistletoe to smooch under this holiday season, look up. It’s quite likely large clumps of this fascinating plant are right overhead where they’ve been hanging out all year in your treetops, acting both nice and sometimes a little bit naughty.
Mistletoe is a smallish, evergreen parasitic shrub found across the globe, including here in Alabama where we most commonly see our native American oak mistletoe (Phoradendron serotinum) growing on the limbs of oaks and other deciduous hardwoods.
Technically, mistletoe is an “obligate hemiparasite,” so named because it primarily survives by living on a host tree or shrub from which it steals much of its life-sustaining water and nutrients. However, mistletoe also manufactures some of its own nourishment through photosynthesis so it’s not as demanding a freeloader as some parasitic pests.
Mistletoe blends in with its host’s foliage most of the year but during the winter its evergreen leaves become quite conspicuous on trees’ bare branches. About that same time, mistletoe also starts to produce vivid white berries and small yellowish flowers.
Those berries are filled with seeds surrounded by a sticky—as in Super Glue-level sticky—liquid. When ripe, the berries burst open and disperse their seedy glue onto other parts of the host tree where they germinate or adhere to the feathers and fur of passing critters that carry them on to other trees. The seeds are also eaten by birds and other wildlife that then spread the seeds elsewhere in their poop. In fact, the name “mistletoe” comes from two old Anglo-Saxon words meaning “dung” and “twig.”
Certainly, mistletoe uses trees and wildlife for its own benefit, but it also greatly benefits nature in the process. Those berries are a major food source for robins, bluebirds, woodpeckers, mockingbirds, sapsuckers, cedar waxwings and many other favorite songbirds and some mammals. Mistletoe’s flowers also feed a number of bees, butterflies and other pollinators, and clumps of mistletoe in trees provide nesting habitat for numerous wildlife species including owls and hawks.
For some wildlife, mistletoe is actually crucial to their survival. Among them are three butterfly species that are completely dependent on mistletoe to complete their life cycles, including the great purple hairstreak found here in Alabama.
Obviously, Mistletoe does a lot of good in our world, but it can misbehave. According to the National Capital Poison Center, its berries and leaves are not as toxic as once believed but should be kept out of reach of small children and pets. And its presence in our trees is not devastating but can be problematic.
Beau Brodbeck, an Alabama Cooperative Extension specialist in community forestry and arboriculture, explained that mistletoe is a slow-growing parasite that causes limb dieback and, though it doesn’t kill trees outright or run rampant through the neighborhood, it can shorten a host tree’s lifespan.
“Unfortunately, mistletoe often takes hold in trees that are already stressed or unhealthy,” he said. And while a couple of clumps won’t do significant damage, it’s negative impact increases as it spreads and the host becomes even more susceptible to other pests and diseases.
The only way to control mistletoe is to fully prune it from the tree—well below where it is attached to the limb—and the degree of pruning needed depends on how much infestation exists. If it’s a tree you really love, Brodbeck recommends using a service that’s certified by the International Society of Arboriculture. (Visit treesaregood.org and click on the “Find an Arborist” tab; search by zip code rather than town.)
He also says the best thing homeowners can do for mistletoe-affected trees is keep the trees healthy by providing them with plenty of water, nutrients and organic matter. Learn more about mistletoe and its control at aces.edu/blog/topics/forestry/controlling-mistletoe-in-trees.
Now, while the leaves are off the trees, is a great time to wander around the yard and assess the mistletoe population in your trees. And maybe get a sprig or two to take inside for your own holiday celebrations.
Katie Jackson is a freelance writer and editor based in Opelika, Alabama. Contact her at firstname.lastname@example.org.