If you have a Megascans Account, you can use various foliage from there (If you render and present it with UE, it’s free, otherwise the personal plan is 20$ for personal and freelance work). You can select different LOD’s to export to Blender. For Placement, i recommend to activate the Scatter Addon in the preferences and then play around.
You can select multiple gras and foliage variants and select the object where you want to scatter over last. Based on your settings, there will be a random distribution.
Another way is to get a foliage texture atlas and follow some tutorials on how to create your own plants and flowers from it. The workflow for this atlas work is always the same and will help you in the long term.
I did some tests back in the day and found out that having as much geometry as necessary to achieve a result similar to the parallax shader would render just as fast as using the shader, so I’d not confidently say that this would be the best course of action. Also, for grass or fur, (which has transparency in the layers) it would require a Shell/Fin shader, which has some similarities, but it’s not the same as the parallax shader.
@nicki.t For grass I’d say that you can’t escape not having to model geometry. Any other solution will not be as good as having actual geometry blades of grass. BUT if you computer is not good, you could have the grass tufts as instances, since an instance is a mesh rendered multiple times equally and therefore without increasing computation time. For this you use the PARTICLE INSTANCE modifier.
First you model a Grass tuft, maybe check this tutorial up to 3:45min:
Now you follow this tutorial on how to use Particle Instance Modifier, video already at the mark:
If you want more variation, since the Particle Instance Modifier only allows 1 object per particle system, create more hair Particle Systems and add another Particle Instance Modifiers for each different object.