Monday, November 28, 2011

Kiss Mistletoe Goodby

Mistletoe has been a part of holiday tradition for hundreds of years. Who hasn't seen a festively ribboned sprig hanging over a doorway, just asking for the next passerby to be kissed? That happy custom dates back to the 17th Century. (Then again, a much older custom, practiced by Druids, promoted hanging mistletoe to ward off evil spirits.)

Courtesy Paul A. Mistretta, USDA Forest Service, Bugwood Org.
All that good and bad mojo aside,  when we purchased our current property last spring, I was less then pleased to look up into a big elm tree alongside the driveway and spot numerous wads of mistletoe decking the branches.

Knowing what I know about the plant, I had no urge to kiss under it. I did, in fact, have an urge to give it the evil eye.

Mistletoe is, after all, a parasite.

There are two major groups of the plant: so-called true mistletoe, which infects oaks, maples and other hardwoods, as well as cypress and junipers; and dwarf mistletoe, which infests pines and conifers (other than cypress and junipers).

Rebekah D. Wallace, University of Georgia

True mistletoe—the stuff of holiday tradition—produces berry-like fruits that birds love...and that's how the seeds get spread far and wide. I was somewhat relieved to learn that the true mistletoe infesting my elm is more or less self-supporting, and doesn't generally do serious damage to a tree. (I say "more or less," because the parasite does drain lots of water from its host, which can be lethal during our ongoing drought conditions. So I'll be doubly careful to keep that big elm well irrigated during dry spells.)

Removing as much of the invader as possible also can help. But the tree is too tall for do-it-yourself pruning. So this winter, I'll have a certified arborist take a look at it, to see if the branches can be cut back a foot from each infestation to help control the parasite. Meanwhile, I'll enjoy the birds attracted to the berries.

The other type of this pain in the landscape, dwarf mistletoe, doesn't require birds to spread itself; it has seeds that are discharged explosively. This keeps the infestation "closer to home." As with true mistletoe, you can help control the dwarf type by pruning away infected limbs whenever possible. This often can help prolong the tree's life and improve it's health.

Chemicals are not very effective in controlling mistletoe. If an infestation becomes serious enough to cause the entire tree to be removed, then it would be a good idea to replace it with a species that is more mistletoe resistant.

Also...this cheerful holiday tradition is poisonous, especially to small children and pets. So while you're smooching under the mistletoe, make sure that no leafy parts drop to the floor.

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