P&PDL Picture of the Week for
December 16, 2013

Mistletoe: 'Tis the Season

Mistletoe may be widely known for its association with kissing around the holidays, but it's actually a plant disease!


Mistletoe is a parasitic plant commonly found in the branches of trees throughout the world. Most mistletoes simply siphon off minerals from the host while photosynthesizing themselves, though some species are entirely parasitic. Heavy infestations will stunt or kill the host tree.

Christmas and other Traditions

Common Christmas tradition is that if a couple happens to meet under a sprig of mistletoe hanging from the ceiling or doorway, they must kiss. Numerous theories abound as to the origin of this tradition, but none seem to fully explain why it exists. The Celts held the plant as a fertility symbol and as a magical healing plant. Mistletoe figured prominently in the apocalyptic tales of the Norse Ragnarok saga, where the beloved god Baldr was killed by a mistletoe dart. This began a series of events that led to the end of the current world.


Birds are the primary disperser of mistletoe seeds. Many species eat the berries; one, the mistle thrush of Europe, is even named after the plant. Some bird species will squeeze out the sticky seed and scrape it onto a branch, whereas other birds simply ingest the seed and pass it through droppings.


Mistletoe is usually a shrubby globe with smooth, oval leaves that are evergreen. White waxy berries are produced in clumps of 2-10. Mistletoe can be easily found in late fall and winter, when deciduous host trees have lost their leaves and the clumpy green mistletoe is visible.


Mistletoe holds an important role in the forest. The berries provide food to many species of birds. The plant itself provides a sort of evergreen aerial shrub that is extensively utilized by birds and other animals for nesting and shelter.


The berries and foliage of mistletoe can cause severe digestive upset if eaten and, in rare instances, may be fatal in humans. Plastic mistletoe is a safe holiday alternative.


Click image to enlarge

Red mistletoe, New Zealand

The sticky seed of the mistletoe on a branch

Mistletoe in Silver Birch

Mistletoe growing in Eucalyptus branches


Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service