Primarily interested in dynamics right now.
Extremely vast subject.

Ideal goal would be to render a single small potted plant that is affected by some type of external force. Turbulence? Velocity field? Fluid? Wind?

And at a more basic level, a single leaf.
How would you model it so that

1) It will have some bend or flexibility

2) Be simple enough to scale up in number

What solver would be best to use?
I've been going thru cloth sim tutorials, wire solver tutorials, etc

Not a whole lot of tutorials out there and the few I could find are quite old.
Any plant experts out there?

I'd definitely go for wire simulation as Houdini stands right now. That solver could let you do what you describe, only exception being leafs to leaf collisions.

If you create the plants in Houdini its also common that you can get the wires for free as they often are created by some kind of underlying skeleton structure.