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Prostrate Knotweed

Best Management Practices:

Prostrate Knotweed

Prostrate knotweed is a warm season, annual broadleaf weed that has prostrate, mat-forming, branched stems.  Its leaves are smooth, alternate, and somewhat blue-green in color.  These linear/oblong leaves join to the stems by a sheathing membrane and its dull brown seeds stay viable for many years.  Its presence is usually considered a sign for compacted soils as well.  

Prostate knotweed begins its life by germinating in the early spring from seed.  Pre-emergent herbicides work by killing germinating seeds from weedy plants like prostrate knotweed.    Normally, an application of a pre-emergent like XL- 2G (Benefin plus Oryzalin), Pendulum 2G or Anderson 11-3-11 (Pendimethalin) or Balan 2.5 G in late February will work well.  Remember, though, that this weed may germinate into the summer—so, a second pre-emergent application in the month of May is recomended.

If your weeds escape the pre-emergent or you do not apply a pre-emergent, you may need to apply a post-emergent herbicide.  These herbicides can be effective if used when the prostrate knotweed is very young/immature and actively growing.  Do not wait until late summer when these annual broadleaf weeds are flowering and mature.   Examples of an effective product to be used are:  SpeedzoneCrab-E-Rad Plus, Weed Free Zone and Trimec Southern.  CAUTION:  Make sure you read the labels carefully for the tolerance level of your specific turfgrass for all herbicides. 

Best Management Practices courtesy of:

Bes-Tex Supply, LLC P.O. Box 664 San Angelo, Texas 76902 Ph. 325-653-1300