Hello!

I am currently instancing a few hundred bushes from speedtree. 
I am wondering, what would be a “simple” way to animate the instances in a small manor? Lets stay I just want the bushes to sway back and forth with some kind of noise added. 

Anyone have any ideas?

Since each unique instance type only supports shader/displacement and render property changes per instance, you will have to generate sequences of tree geometry with motion on them. Then use modulate to cycle over the tree sequences when you instance them.

How you deform the trees is a different question. I am not familiar with SpeedTree these days but if it spits out a skeleton (like I remember I think…), then you can use the Edge Transport SOP to crawl up the trunk-branch skeleton curves (fuse the points so branches fuse to branches etc. fuse to trunk).

Edge Transport SOP creates a distance attribute starting at the point you choose which should be the base of the tree. It's a distance attribute that allows you to add more movement the longer the distance. If there is a width or thickness attribute even better to help add deformation.

Then drive the skinned tree with the skeleton.

Leaves should be instances with instance points. Hopefully they have a local frame of reference (N and up or an orient matrix) that is super easy to sway about with vex.

Then generate your sequence of deforming trees as a cycled animation to disk wedging as many as you want.

Generally 10 instance sequences per type of trees works well enough with a cycle length of 4-5 seconds.