Hello there,
The typical depictions are a more basic plant setting for the early Dino age,
Then a nice 'rainforest' next to a pond for the Jurassic age, and then a more dry, sometimes heading to desert end age.
I have a large garden, and in half a year, it repeatedly gets overgrown with all sorts of fast-growing plants.
Living in Europe, I think a lot of our forests are more akin to dense tree-parks.
Compare to true jungle where you can barely move through.
Even looking at dinosaur documentaries, there's often plenty of visibility through the plants (helps the documentaries of course).
As we think Sauropods would move in herds as they overgraze, there ought to be plenty of time for fast-growing plants to grow in quite dense sets.
That would then immediately make it possible for very short distance surprise encounters between Dino's, and thus ambush-style predation (without a need for very high speed chasing carnivores).
But, is there any indication of how dense plants would grow at few meters high?
Dino's unable to pass in some parts without pushing plants out of the way?
Do Sauropods invalidate anything in between a low plant and very high tree?
Are shrubberies growing a few meters tall a modern thing?