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Sunday - September 16, 2007

From: Pflugerville, TX
Region: Southwest
Topic: Invasive Plants, Trees
Title: Flashing barrier to Bermuda in tree bed
Answered by: Barbara Medford


I'm building a 6-ft-diameter planting bed on a gentle slope on blackland clay, at the center of which I plan to install a cedar elm. I'm using the wedge-shaped stones from the home-improvement store and plan to raise the soil a couple of inches and level it inside the bed. I have also installed 10" flashing inside the perimeter in hopes of impeding the evil bermuda, but now I am wondering if that will also impede the roots of my tree and cause them to circle. Should I remove the flashing and fight the grass some other way? The flashing would be 3 feet away from the trunk in any direction.


The flashing, especially 3 feet away from the roots of the Ulmus crassifolia (cedar elm), should not cause any problems with the tree roots. After all, when you see the damage that is wreaked by tree roots on sidewalks, foundations, sewer lines, etc., why should a little piece of metal bother it? Actually, the only time you have to worry about roots circling is when the plant stays in a confining pot too long. If you purchase the tree in a pot, be sure and check before the tree goes in the ground. If, indeed, the roots are circling or "girdling", do some root clipping (and you can be pretty ruthless) to force the roots to spread. By the time the roots get to your metal flashing, they will be perfectly able to dive under and continue their progress. And, sorry, but it's doubtful that the flashing is going to be much of a deterrent to the Bermuda grass, either. With above-ground stolons and below-ground rhizomes questing for fresh territory, it's tough to block out. But, hey, anything is worth a shot, and your idea seems sound. If it works, let us know.


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