Why is some of my foliage black?

Hi.
I am using a tetxture with an alpha channel for foiliage and Im happy with the result appart from the side thats not facing a light source fully, just looks black. The material is two sided but I dont know what else is wrong. The scene is set at night so that may have something to do with it. One side of the texture in the veiwport is darker than the other.

I would really prefer it if both sides were evenly light, or at least see how it looked.