herb robert

Question

I read somewhat how to get rid of herb robert. pulling it out or mowing if in the yard but nowhere did it say how to get it out of my lava rocks. I pulled everyone of them last year and they have come back with a vengeance. Is there a safe spray to help control this plant?

Answer 1

These articles will help you.

https://www.gardeningknowhow.com/plant-problems/weeds/herb-robert-control.htm
http://your.kingcounty.gov/dnrp/library/water-and-land/weeds/BMPs/Herb-Robert-Control.pdf