Thats a Poser render, it may help to turn off  shadows for the rose, the thing is shadowing itself , which can look very nice but also makes it look bad in some light setups.

The pic is a render in poser, center is the aarose , right one is rose with shadows off , left one is rose with normals reversed for petals, rosehip and leaves . The leaves and rosehip stand out better  but the petals are a disaster   :(

Nomals forward on the material will do the same thing for leaves and rosehip.

Model is attached for you to look at.