Tuesday, January 6, 2015

Mistletoe - Kissing Plants, Thief Trees and Dung Branches

Clumps of Eastern (American) Mistletoe in winter along the Eastern Shore

     One of our more interesting plants is often not noticed until the Christmas holiday season. Eastern Mistletoe (Phoradendron leucarpum, sometimes listed as Phoradendron serotinum or P. flavescens) has evergreen leaves that are visible in winter and has all sorts of traditional uses associated with its European cousin and other species that have since been transferred to our native species.
     This plant is actually a hemiparasite. Its Genus name Phoradendron actually translates from Greek to mean "thief tree." Although it is evergreen and can photosynthesize much of its own energy, it anchors itself and steals water and sometimes some other nutrients from its host tree. It is not usually as harmful to the trees as some of its relatives in the American West and in other countries. That is unless the tree is already stressed, has a lot of mistletoe plants, and/or there's a drought, then it might cause some harm.
Mistletoe growing on a low burl of a honey locust tree trunk in Alexandria, VA.

     Its most common name of "Mistletoe" is derived from some Anglo-Saxon words that basically translate to "dung branch." This is a fitting name since birds such as cedar waxwings and bluebirds do indeed like to eat the white "berries" (technically called drupes), especially since they ripen in winter when other food sources are scarce. The resulting bird droppings carry the actual sticky seeds and may land on a branch of one its favored tree hosts. More so, because the sticky fruits cling to the bird beaks, they often wipe their bills on a branch and the seeds then cling to the bark. This I believe may be the reason that one tree can have multiple mistletoe plants growing on it, while a tree of the same species that is right near by may not have any at all. The birds often wipe their beaks after eating on the same tree they fed upon leaving more seeds.

Eastern Mistletoe with its white, sticky fruits

    The seeds and the fruits (drupes) are very sticky due to a substance called viscin. As they stick to the tree bark, specialized roots called haustoria grow from the seed and penetrate the bark, embedding themselves into the cambium layer of the host tree, the layer that transports nutrients and water.
     In an interesting twist of fate, the fruits are so sticky that many mistletoe species had their sticky fruits collected to make "bird lime" that was painted onto branches as a glue to trap birds. Francis Porcher, in his Confederate ethnobotanical treatise, actually mentions this as one of its uses during the Civil War. He also mentions using Mistletoe to treat epilepsy, paralysis, and even prevent rotting sickness in sheep.
     Its alternative name of the "kissing plant" probably had its origins in a Norse legend. Balder, god of light, had a dream foretelling of his impending death. His mother Frigg, goddess of foreknowledge and wife to the king of the gods Odin, made it her mission to make every living creature and plant swear to cause no harm to her son. She overlooked Mistletoe however, and according to some versions of the tale, the mischievous god Loki tricked the blind god of darkness Hoder (Balder's brother) to make an arrow from the mistletoe which then killed Balder. In her grief, Frigg's tears brought him back to life. She then commenced to kissing anyone who wandered under the Mistletoe-covered tree in her joy.
     So was supposedly born the tradition of kissing people under Mistletoe, though originally you plucked a fruit every time you kissed someone and stopped kissing people when the last drupe was gone. In some places, the mistletoe that had been harvested was burned after the holidays so the people who kissed under it would not marry.
     It was the unusual trait of being evergreen and producing fruit while most other plants, including the tree it lived on, were dormant, that appeared magical to some cultures. Druids would try and tap into the magical nature by following careful traditions when harvesting it. It had to be collected ritually using a golden sickle during the winter (and sometimes summer) solstice and was not permitted to touch the ground. This is quite the departure from the practice of shooting a sprig off a tree with a .22 caliber rifle, which is what is done in some locales now a days.

 A sprig of evergreen Eastern (American) Mistletoe leaves.

     Mistletoe is said to have many magical and medicinal powers. Some traditions involved making warring factions disarm while under it, or feuding spouses kiss and make up. It was said to be an aphrodisiac and a fertility aid (easy to believe with all that kissing), though the fruits themselves are toxic to people. Paradoxically, it was said to protect against poison too. Hanging a sprig over a doorway would supposedly keep evil spirits and witches at bay. The leaves were said to be a good treatment for blood pressure issues when made into a tea as well. Some even believed that when fashioned into a divining rod, it could find buried treasure.
     Native American Indian tribes were also documented using Mistletoe. The Cherokee would use it to treat head aches and convulsions. They also traditionally used it to treat love sickness (by ingesting it for 4 days and purging yourself of the problem through vomiting). I guess it would be easier to forget someone if you were that sick, come to think of it. The Mendocino people used it for such variable applications as abortions and to treat tooth aches. Other tribes were said to use it to treat hypertension and even as an oral contraceptive.
     Mistletoe is a bit mysterious as to which tree host it grows on. In some parts of the country they favor oaks, while in others maples, and still others a variety of trees such as honey locust, hickory, pecan, and black gum. Over 100 species of tree have been shown to be able to host it, though to a much lesser degree and variable by region.
     While we normally do not think about Mistletoe outside the holiday season, it is quite valuable to wildlife. It is relished by birds, as has been mentioned, while others favor it to nest in it as well. It also is the sole caterpillar host plant for the Great Purple Hairstreak Butterfly (2 other butterfly caterpillars feed on the Dwarf Mistletoe species in Western North America). A moth called the Mistletoe Marblelet also has its caterpillars utilize it for food. So while we may consider it a "kissing plant," "dung branch," or simply a parasitic evergreen plant, to many others it has meant many other things. To wildlife it is simply food and shelter.


  1. Thanks again another great post about something in our world I always wanted to know more about. I see big clumps of mistletoe growing in a group of oak trees on Route 66 near the exits for Fairfax Parkway for many many years each time I drive by in winter. Glad to know it is a good food source for birds and a host to the Great Purple Hairstreak butterfly.

  2. I had no idea that mistletoe grew nearby! Thanks for the information.