There is a section of the genus Solanum, that at least in their juvenile stage are perfect for terrariums. This section, Herpystichum is noted for it’s trailing and climbing habits and it’s adventitiously rooting at the nodes. There are 10 species, and supposedly these have narrow distributions. In recent years, there have been multiple introductions of very similar looking plants from Panama, Colombia, and Ecuador. All have fallen into the catch all name of S. evolvulifolium. While the juveniles all look very similar, they could very easily be different species.
Growth in the terrarium can be quick and easy. Resulting in very pretty groundcover or backgroundcover. Rooting is fairly shallow, so trimming or large scale removal is easy. Still for some, it is a little too much. Luckily, there is one plant from Colombia that superficially resembles S. evolvulifolium that is much slower growing, as well as being smaller in size. This one with it’s 1/2″ leaves, is perfect for even small terrariums. And if you like dark colored plants, then you are in luck. Dependent upon the amount of light it receives, the leaf color can range from a very dark green to what seems like black. My favorite is when it takes on a slate gray color. I think it is very attractive this way as it grows among the other plants.