Symbol of peace is a pest

One of the best things about the leafless season is watching goldfinches eat the seeds from my birch catkins. They demonstrate amazing acrobatic skills as they eat, often hanging upside from the dangling catkins.

On the other hand, one of my least favorite things about the leafless season is seeing all the mistletoe growing from our valley's oak boughs. A leafless oak, with its incredible architecture, can be as beautiful as one in full spring bloom or when leafed out in summer. Mistletoe disturbs this elegance for me. Worse, it seems to infest some trees and stunt the growth. We've all seen dead branches protruding from the bundles of mistletoe.

Well, you can't criticize a native Oregonian without scientific backup, so I decided to check on my suspicions. Is mistletoe a benign plant — useful as romantic inspiration — or a killer parasite?

The answer depends on whom you talk to, or maybe which state you live in. Oregon State University's Extension Service press release on mistletoe says infestations of 15 to 20 plants seem to be a problem, but calls the plant benign, ending the story with the line, "Let a sprig of oak mistletoe bring peace and happiness to your home this holiday. Sealed with a kiss." (

While you're cutting down that happy sprig, the California Extension Service recommends you keep snipping until this killer parasite is completely removed from the tree. Apparently birds such as robins and cedar waxwings love the seeds and spread the plants by dining and dropping, if you get my meaning. The seed pip is released through digestion, sticks to lower boughs, and a new plant is on its way.

The California advice continues: "For treatment of existing trees it is important to remove mistletoe before it produces seed and spreads to other limbs or trees. Mechanical control through pruning is the most effective method for removal." (

Removal is an exaggeration. The only sure way to get rid of mistletoe is by cutting off the branch. As you can imagine, that rather disturbs the tree, and local experts, including Max Bennett at the Jackson County extension, don't recommend it. Trees need the leaves for nourishment, he says. And sometimes it's not the mistletoe, but age that is causing a tree's decline.

Instead, routine maintenance means repeatedly cutting off the mistletoe plants every few years. Maybe Southern Oregon could have a new industry, as I'm pretty sure we have enough mistletoe to supply the world.

"People do have strong opinions on mistletoe, that's for sure," says Katie Mallams, a U.S. Forest Service plant pathologist. She agrees that a few plants may not be a problem, but an infestation may diminish vigor and possibly shorten a tree's life.

Here's why. Mistletoe feeds on its host, taking water and nutrients. That's obvious from observing branches loaded with these parasites. The branch and heavily infested tree may die, according to California extension officials, "especially if they are stressed by other problems such as drought or disease."

So here's why I've become an anti-mistletoe militant. Climate change ensures rising summer temperatures and lengthening dry seasons in our valley. As California knows through experience, mistletoe could become a much more dangerous pest for our oaks.

Besides cutting down mistletoe in the trees you love, you can help ensure their survival by deep watering in late summer, but ONLY when the landscape seems stressed by high temperatures and extended dry seasons. In general oaks don't like summer water. It must be deep watering, says Mallams, such as a trickling hose left running for hours.

With a landscape plan like that, there should be enough mistletoe for robins and cedar waxwings, with extended life and health for oaks. As for peace and friendship, this is the season for that blessing. Hope it fills your home, with or without mistletoe.

Master gardener Althea Godfrey is gardening editor for HomeLife magazine. Reach her at

Share This Story