Quote - import those plants into Unreal and you can use Unreal's painting tools to paint those plants wherever you like, and again, all in realtime

And what makes that even nicer is, that  one 1,000 polygon tree is still 1,000 polys, whether you have just one copy of that tree in your scene, or 100,000 copies of it, because it's all instanced. I've been hoping Poser would implement instancing, and LOD, for a long time now, but there doesn't seem to be any sign of that coming.