Released June 28, 2007
MANHATTAN, Kan. - Liquid (herbicide) "edgers" can eliminate the whacking-weeding needed along fences and streets, as well as in gravel drives, retaining walls, dry-set pavers and sidewalk cracks.
For the safety of nearby landscape plants, however, liquid edgers require careful use. In fact, one type can do its plant killing either above or below ground, said Gregg Eyestone, horticulturist with Kansas State University Research and Extension.
"Some edger products - including glyphosate (Roundup) and glufosinate (Finale) - rarely cause accidental damage. At this time of year, you´d have to directly spray a desirable plant´s foliage," he said.
But, other liquid edger products are soil sterilants. Once applied, they have a long residual life, remaining active in the soil from months to years. They also are highly toxic to trees and shrubs, causing leaf yellowing, marginal leaf scorching, branch dieback, and sometimes tree or shrub death.
"You must never use soil sterilants where desirable plants´ roots could be exposed," Eyestone said. "Once plants take up a sterilant through their roots, the damage is permanent."
Tree roots extend well beyond the so-called "drip line" - the soil under the leaf canopy´s edge.
"In the average landscape, that makes safely using this kind of liquid edger almost impossible," he said. "You can´t even assume roots won´t grow under walks or drives."
A subcategory of the soil sterilants includes prometon, which is sold under various chemical, as well as trade names. (See both at http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35130.)
Until they become affixed to the soil, prometon-based products will move with water - rain or irrigation, Eyestone said. This can expose more distant plant roots, plus pollute natural water supplies.
"The key is to scrutinize labels to see what you may be buying and how to use it safely," he said.
--30--
http://www.oznet.ksu.edu/news/sty/briefs.htm#Four
Contact: Mary Lou Peter-Blecha, mlpeter@ksu.edu
