Mullein (Verbascum thapsus) in a post-fire environment. Mullein seeds can lay dormant for a century awaiting the disturbance habitat they prefer. January 1, 2024 by Kollibri terre Sonnenblume Mullein (Verbascum thapsus) in a post-fire environment. Mullein seeds can lay dormant for a century awaiting the disturbance habitat they prefer.