Friday, July 8, 2011
Preen for Garden Weed Control -- Just what’s in that stuff anyway?
Today the Preen name is used to identify a diverse product line that includes preemergence and postemergence herbicides. Several Preen products contain 2,4-D for broadleaf weed control in lawns; these products should not be used in landscape beds. The active ingredient in Preen Weed Preventer for Southern Gardens is dithiopyr – the same ingredient found in the herbicide Dimension. This is safe on most ornamentals but should not be used around any food crops. There is Preen Mulch Plus Premium that contains isoxaben plus trifluralin (think Snapshot TG); not to be confused with Preen Plus Mulch Midnight Black that contains trifluralin (but no isoxaben). The isoxaben-containing mulch will damage pansies but the trifluralin-containing product will not. Confused yet? There is also Preen Brush Weed Killer that contains 2,4-DP + 2,4-D + dicamba; Preen Weed and Grass Killer that contains glyphosate (same ingredient as Roundup); and an organic product for vegetable gardens, Preen Vegetable Garden Weed Preventer, that contains corn gluten meal. Many different active ingredients, all sold under the Preen name can lead to confusion.
So, if you go to the garden center to purchase Preen for weed control in your garden or lawn – READ THE LABEL. Make sure you purchase the right product for the right job.
Labels and material safety data sheets for the Preen products are available from the manufacturer’s web site at http://www.preen.com/msds
Written by: Joseph C. Neal, Professor and Extension Specialist -- Weed Science