How to animate petals opening I need to make a set of rectangles standing up on the edge of a circle close inwards and fan outwards. They aren't actually petals but it seems like an intuitive way to explain it.

In the image I've gotten the geometry I want by using dupliverts, but I can't get that to work for an animation. It doesn't orient correctly unless the child object's rotation is reset with Ctrl + A. I tried animating array modifiers, but the rectangles distort.
I don't think using constraints will allow me to get all the rectangles to nicely spread each in a different direction. I am wondering now about drivers, but I've barely used constraints or drivers. Also it would be really nice to keep the aspect of having one shape determine the shape of the others, so I can edit the shape of all of these blades at once later on if I want to.
How should I approach this?
so, with Dupliverts:


Create your circle, create your petal, apply the rotations, parent the petal to a bone With Automatic Weight.
Select your circle, in the Properties panel > Object > Duplication, press the Verts button, enable Rotation.
Parent the armature to the circle. The petal should duplicate along the circle.
Animate the bone in Pose mode, it animates the other petals.