Encounter/terrain ideas — Kudzu

[QuickLyRaiNbow]

Of all places the party could have chosen to use as their home base, they decided to start in the part of the map where the terrain can be described as "Kudzu". A large area of creeping, invasive vines that choke out all other plant life, and which the locals are trying to control by intentionally overgrazing with sheep and finding every possible use for the stuff.
I'm sure there are lots of creative ideas for what kind of things would be found in this terrain, but I don't have familiarity with it myself. I'm not even sure if I should compare travel speed to grassland or to thick forest. Any thoughts?
If it helps, the system is EZD6, and the party races are all originals. Fantasy.

I'd say thick forest unless in recently-grazed areas, or perhaps permanent paths controlled by constant grazing.

I'd also have, I think, something akin to Old Man Willow and the Withywindle at the center of the area. The vines create their own paths, trying to draw the unwary or the careless into the heart of the ravenous growth. That entity could be some sort of plant elemental, like a shambling mound or a treant or something, or it could be something more like a genius loci.