Once autumn leaves have fallen, mistletoe becomes highly visible on large trees throughout Kentucky. Phoradendron, the scientific name for Kentucky’s most common type of this parasitic plant, means tree thief. These small leafy plants are commonly found on twigs and branches of many hardwood species in the southern United States. Mistletoe extracts (steals) water, mineral elements, and food from tree hosts; hence the name.
Mistletoe use in holiday traditions has roots in pagan times. The appearance of a live parasitic plant while the host tree appears dead led some to believe mistletoe mysteriously held the life of the tree during winter. Druids harvested mistletoe in a special rite, never allowing the plant to touch the ground, and then hung it in their homes for good luck.
Our modern-day mistletoe holiday tradition likely originates with a mythological Norse goddess of love and beauty. Frigga, whose son was restored from possible death by mistletoe, was thought to bestow a kiss on anyone walking beneath one. Today, when two people meet under the mistletoe, tradition suggests they must exchange a kiss for good luck.
Phoradendron has simple, fleshy green leaves arranged oppositely on stems (Figure 1). Stems are short and more branched than host trees, so mistletoe often appears as a spherical bunch of dense vegetation (Figure 2). These bunches may be a foot or two in diameter and are located high in the tree where sun exposure is greatest. Mistletoe berries range from white to straw-colored to light red. Birds eat the fruits, reportedly toxic to human and animals, then deposit the seeds onto branches where they germinate and penetrate the next host tree.
Mistletoe commonly appears in open-grown trees where birds tend to roost, thereby less frequently in forest trees. Generally, mistletoe causes minimal damage, although it can be harmful to stressed trees. Mistletoe can be removed from landscape trees by pruning.
- University of Kentucky Plant Pathology Extension Publications (link)
By Nicole Gauthier, UK Extension Pathologist