Sorry for not getting back to this thread with an example sooner, I forgot.
I'm attaching the .tgd for this image;
I have left all the shaders in the main node network view for ease of access, if you make a new grass clump, the shader will be inside it and you should set the wind shader to it with a right-click on the 'displacement function and selecting the transform shader from the node list menu. (or, just create the shaders inside the grass clump node but you might want to use the wind nodes for more than one object, leaving it in the main node network makes it easier to find and apply to each model you like).
The power fractal is set to scales='1', you
don't need to apply any displacement here, it won't have any effect.
The transform shader moves the fractal colour upwards(Y) by 5m over 50 frames.
The 'default shader' uses the transformed fractal colour as its 'displacement function'(value='1')
* To see the effect of the wind, open the 'shader preview' window for 'default shader 1'. I've set it to around 3m so we are quite close to the shader. Move the camera and then just advance through the frames, you will see the shader preview update in real time.
Download .tgd[attachimg=#]