My original idea was to have two textures, one for the leaves and another for the branches, change the color of the leaves texture and then stack that texture on top of the branches texture. However, I’ve been looking through the documentation and haven’t see any blend modes or anything that would allow me to do this.
You could use a mask texture, just highlight the leaves in your texture with white, then black out everything else, and be sure to apply that to your alpha channel.
If you have made your mesh in Maya then you can assign two maya materials to the separate geometry. now when you import into unreal you get one static mesh but two separate materials.