In the front lawn of my house is an oval rock garden that the previous owner tried to plant shrubs but never maintained it to a point where weeds were EVERYWHERE. Two years ago, I pulled out as much weeds as I can and all old shrubs out of the ground and planted new shrubs. I spread garden food immediately then weed control 2 months after and repeated that cycle. I covered the entire rock garden with black mulch for a beautiful look.

Last spring, the rock garden started getting weeds growning in many different areas. Along the entire inside edges of the "oval" rock garden grass started growing. Previous shrubs started growing up again making the rock garden look very messy!

Should I have installed that weed carpet two years ago before laying out the mulch? Even though I have existing shrubs in now with mulch, can I still install the weed carpet across the entire oval rock garden then cover it up with another 3 inches of mulch? Is it OK to spray the ortho weed and grass killer in the rock garden to kills all weeds and grass? I dont want to kill my existing shrubs. Please help! Thank you!

 

Weeds can grow in mulch so while the landscape fabric helps it's not going to prevent weeds forever. I spray the weeds with herbicide like RoundUp or any other herbicide that contains glyphosate. Glyphosate is only absorbed through the green/leaves of a plant so as long as you don't spray the shrubs you will not hurt them. Clay in the soil rapidly binds with glyphosate making it inactive so it's pretty safe to use close to other plants.

 

I"m not an expert, but I would do just as you describe with the carpet (cutting around the stuff you want to keep of course) and then more mulch on top. As for the week killer, the label likely addresses if its safe. I'd make sure my aim was precise and don't do it on a windy day. Thats all I've got