Sawtooth Association

The Alpine Examiner

July 24, 2023

Naturalist Blog

Getting to the heart of what matters in the Sawtooth National Recreation Area

Below the Mistletoe

“Kiss me under the mistletoe” is a common phrase we hear around the holiday season, as romantics hope to receive a peck beneath their door frame. For centuries people have glamorized the mistletoe and its association with love, but it is the furthest thing from love as it slowly kills trees and shrubs worldwide.


Mistletoe is a parasitic plant that steals nutrients and water from a host, cone-bearing trees and shrubs, ultimately leading to mortality. There are over 1,500 different species of mistletoe that range in toxicity. There is one species of mistletoe in the Sawtooth’s, known as dwarf mistletoe.

Dwarf Mistletoe. Photo by Franco Folini, Wikimedia Commons

Arceuthobium, its scientific name, differs from other variations of mistletoe as they are smaller in size and only attack species within the Pinaceae (pine) family. In the Sawtooths, their hosts are primarily Lodgepole Pine and Douglas Fir. The pathogen is a seed-bearing plant with both male and female parts; upon germination, it begins to spread twig-like branches that are yellow/orange in color. As the mistletoe robs the tree of nutrients, it will get larger and form a structure known as a “witches’ broom.” 


The growth process takes several years, and the tree will begin to have an abnormal structure and less seed production as the mistletoe continues to steal resources from it, ultimately weakening the tree. This makes it more vulnerable to drought and other diseases and pests, such as the mountain pine beetle. Once the mistletoe has spread throughout the crown of the tree, it will take about ten years for mortality to occur. A long process that can be prevented by pruning infected tree branches!


So, while the trees in the Sawtooths are decorated with this unwelcome parasite, we question how mistletoe is anything close to love.


Mistletoe’s thieving habits have been around for centuries. In 100 A.D., Celtic Druids observed the presence of mistletoe and its ability to live even in the harsh winters. Unaware that the plant was parasitic, it soon became a symbol of fertility for its ability to thrive despite the conditions.


Other cultures had similar associations with mistletoe. In Norse mythology, there is a story about the goddess Figg, who had lost her son to an arrow made of mistletoe. After his death, she felt the plant should no longer be used as a weapon and swore that one would receive a kiss whenever they walked beneath the plant.


The use of mistletoe continued for the years to come; some cultures used it to ward against witchcraft, others as a tool for healing, and some just to represent love. The Christmas tradition of kissing beneath the mistletoe began in 18th-century England and continues today.

Image sourced from

So, on your next endeavor within the Sawtooth Wilderness, observe the mistletoe feeding from the area’s beautiful trees. The relationship between organism and parasite is far from the sweet traditions surrounding it.


Fiona is a Naturalist for the Sawtooth Historical and Interpretive Association. She spends her free time exploring the mountains, whether hiking, trail running, or backpacking!