Mind the mistletoe




 

 

Q:
After leaves started falling off the large sycamore tree in my front yard, I noticed that some of the areas of my tree, way up on the top, are still green. Talking to a neighbor, he said the patches are mistletoe. There are three “globs” of it about the size of a basketball in different areas of my tree. What causes mistletoe, and what should I do about it? Will it harm my tree?

A:
Mistletoe is a parasite that attaches itself to a branch or main stem of a tree. The reason you are seeing it now and not the rest of the year is because mistletoe is an evergreen organism and your sycamore tree is deciduous, that is, it loses its leaves in the fall. Now that the tree is devoid of a thick covering of leaves, the mistletoe jumps right out at you.

The most common trees infected in the Conejo Valley are ash, oak, alder and sycamore.

Mistletoe, through its berries, can be spread from tree to tree and from one part of a tree to another. The berries of the mistletoe plant are extremely sticky and will cling to birds or squirrels that brush against the plant.

The berries then hitch a ride on the fur or feathers of the critters to another branch or tree, where they are deposited and begin to germinate. It’s even said some birds eat the berries and, while perched on a branch, sort of, well, you know, deposit
them strategically.

As the seeds germinate, they put out small, rootlike tentacles that find their way into the sapwood of the new host tree. After the mistletoe is firmly attached, it receives all of its water and nutrients from the vascular system of the host tree.

As effective as this process is at maintaining life for the mistletoe, it adversely affects the health of the host tree. As the mistletoe grows and expands, it steals more of the life-giving water and nutrients that the tree needs to maintain health.

The easiest way to control mistletoe is to cut off the branch it’s growing on. By eliminating the plant and the berries it produces, there is little chance for the parasite to expand its range.

If it’s not possible to cut off the entire branch where the mistletoe is located, at least cut the mistletoe stalk off as close to the bark of the tree as possible. This won’t eliminate the mistletoe in the tree, but at least it will prevent it from spreading.

The larger the mistletoe plant is, the more it can harm your tree, so controlling it is the key to keeping your tree as healthy as possible.

If you look at a glass as halffull rather than half-empty, there’s a positive side to having mistletoe in your tree.

Most people associate mistletoe with Christmas. You can find it packaged in small bags for sale in almost every store in December. The little bundles of mistletoe are wrapped in a red ribbon and are hung in doorways during the Christmas season in hopes of stealing a kiss from a sweetheart who wanders underneath it.

I’m not sure how this custom started, but millions of bags of mistletoe are sold every December for just this reason. You have enough in your front yard tree to start a small business.

I remember when I was 10 years old I earned Christmas money selling little bags of mistletoe to all my neighbors. My father and I had gone up to the San Gabriel Mountains and collected a car-trunkful of the stuff, which I took and packaged in small bags. Even at 25 cents a bag, I actually did pretty well.

An important side note is that eating mistletoe can be deadly to humans. Many wild animals, however, especially deer and elk, think of mistletoe as candy. They will migrate toward the sound of chainsaws in the mountains where logging is being performed because they know the mistletoe will soon be on the ground.

For humans, however, ingesting the plant is a definite no-no. That’s why it’s so curious that it’s used as a reason to steal a kiss from a cutie who stands underneath it. I guess more research has to be done on that one.

David D. Mortimer is a certified

arborist with more than 30
years’ experience in the tree care
industry. E-mail questions to
dmortimer@theacorn.com.


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