Foliage

To quickly add small meshes, like grass, rocks or others, you can use the foliage editor, on the top left corner. It is similar to adding a texture on terrain mode. The downside to it is that it adds a lot of meshes, so it will consume a lot of memory, decreasing performance. Use it in small doses to enrich your level.

Added foliage

To add the foliage hold Ctrl+Left Click and to remove them Shift+Ctrl+Left Click.

Foliage options

To select which meshes will be used simply drag them from the content browser to the foliage editor. On Brush Settings, you can change the brush size, density and where will the brush be applied to.

Foliage menu

On the Meshes side, you can change rotation, size, scale and many others. It is interesting to change the min and max scaling to add more variety and detail.

Editing individual mesh