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Letter to the editor

Picking the right weed-killing specialists

By Dean Fosdick, Associated Press
Published October 6, 2007

Scientists are screening the effectiveness of scores of natural weed-killing plants commercially available for almost any spot in the yard.

Some of these weed-suppressive species may surprise you. Take ferns, for instance.

"Looking at the literature related to ferns growing in woodland conditions, early botanists noted they produced nearby sections of composting leaves and dead shoot material," said Leslie Weston, a consultant and recently retired weed scientist at Cornell University, Ithaca, N.Y.

"They discovered ferns were very complex and biologically active, making many of them weed-suppressive. A case in point is the Japanese painted fern. They can discourage weeds while at the same time provide color and texture in the landscape."

Here are some other attractive weed-suppressive perennials rated good to excellent by Cornell researchers, either for their sun-denying canopies or their naturally occurring volatile chemistry.

Shady spots

Thyme, a grasslike plant with red foliage and purple summertime flowers; coral bells, a clump-forming plant with deep red foliage and delicate pink flowers; bigroot cranesbill, a sun-to-shade varietal with foliage that turns crimson in autumn and produces creamy white or pink flowers in summer.

Full sun areas

Dwarf goldenrod, an upright plant that produces yellow blooms in late summer; catmint, another upright, this one offering blue flowers in summer; lady's mantle, a clump-forming cultivar, with large, round leaves that hold droplets; it also produces bright yellow flowers.

Water-deprived areas

Heath aster, which grows in a dense clump thick with flowers in early fall; hardy ice plant, a mat-forming or trailing succulent that produces light yellow flowers in mid to late spring; creeping baby's breath, a mat-forming plant with white to purple flowers in the spring.

"They're generally aesthetically pleasing and sustainable, with low maintenance," Weston said.

More information about weed-suppressive plants, their effectiveness and cultures is available on this Cornell University Web site:

www.entomology.cornell.edu search "groundcovers."

[Last modified October 4, 2007, 18:25:09]