Corey, the walnut is the tree on the right. I'd say it's out of juice...You should concider cutting the walnut out of your plot. I recently learned walnut trees release a herbacide called Juglone as a defence mechanism to stop other plants from growing with-in their dripline . That herbacide is probably restricking some of your germination. Obviously, from your b4 picture, plants can/will grow but I have always noticed that below walnut trees there never seems to be an over abundance of vegitation. Just a thought