Not quite insect or disease, just a problem invasive! I have a smallish area that got a bit of Johnson Grass, and that bit getting more. In small areas, has anyone here just tried digging it out? The roots are rhizomes and tough, so it can't just be pulled out. There were some 'keeper' plants in the area, but not so much anymore. I am working to make a pathway across, perhaps 10' long. The grass is thick in that area. I have thought to cut it back to ground level, put down cardboad, then wet, and lots of mulch. RoundUp is looking tempting, but spot way too close to lots of good stuff!