Cryptocoryne Wendtii

Native to Sri Lanka, Cryptocoryne wendtii is probably the most forgiving aquatic plant you can put in a tank. It comes in several color forms including green, brown, red, bronze, and the compact Tropica variety, so there's almost certainly a form that fits your aquascape. Leaves are lance-shaped with a subtly textured, slightly wavy surface, and depending on light intensity the coloration can shift from olive green to deep reddish-brown.

Growth is slow and steady rather than explosive, which makes it easy to manage without constant trimming. Plant it in a nutrient-rich substrate for best results, though it will muddle along in plain gravel if you dose fertilizers. It fills in nicely as a midground specimen or even a loose foreground cluster in larger tanks.

Propagation happens naturally through runners that emerge from the base, so over time you'll get a growing colony without doing anything special. New plants can be separated once they've established a few leaves.

If you want to see how wendtii looks once it's really settled in, tank builds posted by hobbyists online show just how lush and full a mature colony can get.