Maybe three crossed planes looks a little bit better. Also did you use the keyword "leaf"? At my last project at Rhino it helped to use a light emissive effect, but I'm not sure it will work at SU.
This problem on foliage disappear when I uncheck face me option, but now their shadows are not realistic in the ground...
This is exactly the problem - either the plane shadows are facing the sun (resulting in good shadows on the ground) or to the viewer (wrong shadows on the ground).
Currently, it's technically not possible for us because we would have to exclude the tree from his self shadow - not from all of course. But the tree model which is used for calculating the shadows is unfortunately facing the sun in this case which then causes usually not-so-good looking self shadowing. As Micha said, the best workaround would be to use crossed planes without faceme.
