I am sorry, I don’t have any screenshots, but I can think of 3 ways for authoring Turf grass within UE4:
Being able to paint Turf grass onto a terrain in Landscape should be an obvious choice
Painting Turf grass on static/(maybe even skeletal) meshes through vertex painting would be very nice and usefull.
Applying Turf grass to a static/skeletal mesh through a material could also be a very hand way to use Turf grass.
Question: Is Turf only limited to grass or will we able to create our own vegetation? Bioshock springs to mind, and the ability to plant subaquatic plants would be awsome.