You need to create the Grass Mesh along the (World) Y-Axis (don’t ask me why, it just works better that way, but you already have your blades modeled, so you can simply rotate them in Edit Mode along the X-Axis -90°, don’t forget to change the Pivot Point!)) and then change the Axis in your Particle instance Modifier to Z. Also change the Hair length, it is still too short (shouldl be more like 4m).
It also helps if you press ALT+G on both the Grass and the Ground (Plane).
