‘Tis the season for stockings hung by chimneys, Christmas trees adorned with lights and ornaments, houses all aglow, and kisses under mistletoe. The history of mistletoe and its romantic role in the holiday season is theorized to stem from several areas of folklore and myth. The most likely origin of mistletoe as a symbolic herb began with Celtic Druids in the 1st century A.D. Unlike most plants, mistletoe can bloom during the dead of winter, so to the Druids it became a sacred symbol of vivacity and fertility. A different origin in the lore comes from Norse mythology, when Odin’s son Baldur was prophesied to die. In response, Baldur’s mother Frigg secured oaths from all living things not to harm her son- but she neglected to secure the oath from mistletoe. Loki made an arrow from the plant and used it to kill Baldur, who was then resurrected. In response, Frigg declared mistletoe a symbol of love and vowed to plant a kiss on all those who passed beneath it. Regardless of which origin story you believe, mistletoe has long been incorporated into Christmas celebration, with the custom being that refusing a kiss under the mistletoe would bring bad luck.
While the origin and story of mistletoe is certainly interesting, the plant itself is perhaps more so. Mistletoe, or “witches’ broom” is the common name for a large number of plants belonging to families Loranthaceae, Misodendraceae, and Santalaceae. In general, mistletoe refers to hemiparasitic plants who attach themselves to and extract nutrients from host trees and shrubs. There are many varieties in each family that prefer different geographies and hosts, including Viscum album, Viscum cruciatum, and Phoradendron leucarpum. The latter is the only species native to North America, otherwise known as eastern mistletoe, which is recognized by short, broad, smooth-edged evergreen leaves, and clusters of more than 10 waxy, white berries.
As a hemiparasitic plant, mistletoe grows on over 200 different tree and shrub species, causing reduced growth, stunting, loss of branches, and potentially death. Since there is so much variation in the types of mistletoe, there is a lot of variation in the parasitic behavior of the plant- some types are able to photosynthesize and rely on the host for primarily structural support, while others cannot photosynthesize and rely on the host for nutrients, water, and support. Mistletoe berries can sometimes be toxic to animals and humans, but in some varieties serve as food sources for birds and pollinators which spread the plant from one host to the next.
At this time of year, it is easy to see when a tree has mistletoe present in its canopy. As mentioned above, a heavy mistletoe infestation can cause significant growth issues and death of its host. It is possible to remove mistletoe by pruning it out two feet below where it attaches to the tree, or by pruning it out completely and wrapping the cut with plastic to prevent it from growing back. With that said, reaching mistletoe in mature trees is often a dangerous endeavor and requires specialized equipment and skills. For most situations, it’s best to simply keep a watchful eye on the host plant and remove it from the landscape if and when it is no longer viable to keep.
If you have questions this holiday season, feel free to contact us at uge3181@uga.edu or 706-359-3233.
