The Verdants were a race of intelligent plants native to Birr, resembling large ambulatory flowers. They hated loud noises, and could throw barbs to defend themselves. When a Rostrow space mission visited the planet, they mistakenly took some of the Verdants prisoner, unaware that they were intelligent beings. Believing the Rostrows to be hostile, the Verdants withdrew underground and used a force field to prevent the Rostrows' ship from leaving.
Soon afterwards, the First Doctor arrived and, quickly learning of the situation, went with Duh to see the Verdants' leader Phlege and make peace with them. After escaping from some Verdant executioners, they met with Phlege, and with the misunderstanding resolved, the Verdants returned to the surface. (DWA: Mission for Duh)