I apparently wasn't very clear-headed in my previous reply, sorry about that. @KeirKieran SouP has a TimeOffset node, but it connects to a shape node, which you're not going to be able to do with instancing. Gonna agree with musashidan that all the grass meshes will need to be unique anyway. So this TimeOffset node would…
Duplicating the object doesn't bring over the animation because I'm animating a cluster of vertices at the top of the grass. If I make the duplicate an instance I get the animation, but then I can't offset the animation because its all driven by the first cluster (unless I'm missing something there). Now, I can Duplicate…