Century plant leaves. Close-up of the leaves of the century plant (Agave americana, variety marginata). This succulent, virtually stemless plant has spine-tipped, sword-shaped leaves which grow up to 1 metre in length. The flowers appear after 30-40 years, once thought to have been a century, which is how the plant gained its common name. It is originally from Mexico, but was introduced to the Mediterranean region in 1640.