Best way to add some color to the terrain is plast plants, got two flowers from the local "cheap junk store" for about €1. And a branch of some kind of plastic bush from Hornbach costing about €5.
Take each layer from the flower and glue it to a small metal disc. Once dry cut of the end, and apply preferred basing materials to the disc.
About the same process with the rest of the vegetation.
Mix it up on the table and you have a nice piece out colorful jungle terrain to explore.