Wednesday, November 9, 2011

Treacherous Beauty

I remember the good old days when, during long walks in the summer, I would pause to admire (covet) wild trumpet vines growing along the country roadsides. Often, a rubythroat hummingbird would be face-deep in a brilliant orange blossom, drinking in its rich nectar. I would think, I'll stop by in late summer and gather some of the seed pods...or maybe find a small vine to transplant next spring. But years rolled by, and I never got around to it.

Trumpet vine (Campsis radicans)
Then some unseen bird made my wish come true by depositing seeds on our property. I can't tell you how thrilled I was to spot a distinctive splash of orange along the treeline in front of our house. I grabbed a camera and commemorated the moment a picture.

The pleasure didn't last. All too soon, we learned why this vine with its glorious blossoms is called a thug.

Our perky little volunteer burgeoned with the rampant enthusiasm of kudzu. Its root system produced vast underground networks (some gardeners who have tried to eradicate trumpet vine claim the roots grow up to 40 feet deep!), and sent up new sprouts that quickly grew into astonishingly robust invaders that rivaled the Mongol Hordes. Attempting to pull up the vines was like trying to pull up a sewer line: the linkages just kept going and going.

We tried mowing, but that only seemed to encourage new sprouts. Neighbors who had been gifted with similar "volunteer" trumpet vines grew so desperate that they set aside their organic practices and tried dabbing herbicides on the leaves. Their trumpet vines laughed.

You might think this was much ado about nothing—after all, trumpet vines are gorgeous, and hummingbirds adore the blossoms. But trumpets can be deadly. They develop woody stems that naturally want to grow up fences, walls, telephone poles...and trees. Grown on a wooden fence, it will insinuate itself between the boards, where it will proceed to slowly tear the fence apart. Allowed to grow up a porch post, it will probe through the tiniest openings until it finds a way inside the eaves and attic of your house.

Trumpet vine growing up an oak tree.
Allowed near a tree, it will shoot up the trunk and fill the canopy with its foliage and blooms. And as the years go by, the stems will grow thicker (I've seen them as big around as my wrist) until they can begin choking the life out of branches.

Trumpet vines aren't alone in their ability to damage or destroy trees. Climate change is resulting in more carbon dioxide in the atmosphere—a boon to vining plants. In the past, vines such as Virginia creeper, honeysuckle, Boston ivy and wild grape could be kept within the bounds of reason. Now they run amok, growing at rates unheard of before. I've even seen wisteria blooming in the tops of tall cottonwoods.

Vines don't have to produce powerful woody stems to do severe damage to trees. Years ago, we had a stand of young oak trees in which a wild grape vine grew. Before I noticed what was happening, the leafy vine had grown to the top of the canopy, spreading in the sunlight and shading out the tree foliage. Deprived of their ability to photosynthesize, the trees died.

Even vine-stressed trees that survive can be so weakened by their unwanted "guests" that they are left vulnerable to extreme-weather events. During drought conditions, these vines drink up scarce water resources that could have gone to the tree. And vine-shaded canopies produce less of the energy that a tree needs to heal injuries or resist pests and diseases.

So these days, I limit vines in my garden to annuals. And when I see any vine growing up a tree trunk, I'm quick to cut it off.

What experiences with "treacherous vines" have you had in your garden?

1 comment:

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