Weeds in my Hypericum perforated beds

Asked May 9, 2016, 10:57 AM EDT

I have some large beds of Hypericum perforatum (St. John’s Wort) mixed in with salvia sylvestris (May Night Sage) that are experiencing lots of grassy weeds and other broadleaf weeds as well as sedge and grass growth from fall overseeding. Any suggestions on how I can treat these weeds and remove the grass without killing the Hypericum perforatum or salvia sylvestris?

Prince George's County Maryland

1 Response

If you want to control the weeds, it is important to identify them. Otherwise, you will have to handpull and mulch the beds with several inches of an organic mulch to keep the weeds down.
Once you have identified the weeds, if labeled, you may be able to apply a preemeergent, as in Preen. There are many products. Some grassy and broadleaf weeds can be controlled by using a preemergent. This will not control existing weeds. You will have to follow label directions for application and look at the plants that this product can be used around.
You can also spray a non selective herbicide that contains glyphosate. This kills all desirable plants and you will have to protect them.
http://extension.umd.edu/hgic/lawns/lawn-weed-identification
mh