I am wondering if there are any products that will kill grass but not harm...

Asked November 5, 2013, 8:40 PM EST

I am wondering if there are any products that will kill grass but not harm perennials? Unfortunately I have grass getting into a number of my gardens and with time it seems no barrier keeps it out for very long. Any suggestions? I probably wouldn't be doing anything about this until spring at this point. Thank you.

Anoka County Minnesota

1 Response

Following is a relevant paragraph from a University of Minnesota bulletin. It's about controlling quackgrass, but the product can be used to control other grasses too.

"In perennial gardens, a selective systemic herbicide containing fluazifop (fusilade) (Ortho-Grass-B-Gon) can also be used successfully. It is important to apply this only to the quackgrass leaves as it may damage or kill all monocots (daylilies, iris, gladiolus, lilies) once it contacts the leaves. This product can also be used with asparagus (non-bearing plants only; you cannot harvest for 12 months after application), rhubarb, spinach, garlic, peppers, onions and non- bearing trees and vines. Grass-B-Gon is best applied to young quackgrass plants with 2 to 4 leaves; two applications are sometimes required to completely eradicate quackgrass. Apply this herbicide when no rainfall is expected for 24 to 48 hours."

Fluazifop requires several days to take effect and more than one application may be needed.

Go here to read the complete bulletin:

Controlling Quackgrass in Gardens
http://www.extension.umn.edu/yardandgarden/ygbriefs/h507quackgrass.html