You can use for the foliage a normal material with emissive light option, select the foliage model and set Use Emissive for static Light. But yeah if you need something more advanced Epic should add a option or you should edit the engine.
You can use for the foliage a normal material with emissive light option, select the foliage model and set Use Emissive for static Light. But yeah if you need something more advanced Epic should add a option or you should edit the engine.