Foliage Issues

Hi, I’m a student and I’m comfortable with Unreal, but not too knowledgeable in it, but I have two problems with foliage in my scene (all foliage is part of the same texture/material)

  1. I have two-sided enabled, but the back side appears much darker than the front side

  2. Some of the foliage with this material are showing through others (with same material)

Any help with either of these?