I haven't tested my soil yet, but I guess it is acidic from decades of pine straw. Here's the healthy mystery plant. I know a flower would help, but...
Here's the ill nourished looking one. You can see it's flower. Not the grass, the mini kale looking one.
The healthy plants are Ajuga reptans, a common groundcover that can be aggressive.
Here is a link that might be useful: Ajuga reptans
Thanks so much tulsarose for the positive id. Having moved here recently, I'm still at the stage of learning what to encourage and what to dig up for municipal composting. If bugleweed inhibits poison ivy 100% it might come in very handy here.
"If bugleweed inhibits poison ivy 100%" No chance. Ajuga is a tiny little thing, PI is a giant vine.
I think the other plant is something different, not Ajuga, but no idea what. There is a name-that-plant forum if it's not recognized here.
Pine straw, like other forms of organic matter will not have a significant impact on your soils pH, and as many of us have found getting an adequate amount of organic matter in the soil can help that soil become more acceptable to a wide range of plants.