Department of Biology

Our large century plant (Agave americana) in the Jordan Hall greenhouse has bloomed and died. A species that blooms once and then dies is referred to as monocarpic. Our plant was estimated to have been over 50 years old and had been the focal point in the cactus/succulent room for many years. Although it’s nicknamed the century plant, the longevity of A. americana is typically 30 years as opposed to 100 years as the name suggests.

In March 2019 the plant began sending up its impressive flower stalk—which looked like a giant spear of asparagus. A. americana is a member of the Asparagaceae family.

The stalk grew to a height of at least 30 feet (which required removing a section of glass to let the stalk pass through the roof), producing horizontal branching near its top. Greenish-yellow flowers 3 to 4 inches in length bloomed in panicles (loosely branched clusters of flowers) at the branch ends. After pollination occurs in the wild, the plant begins to produce seeds and forms plant shoots at its base. After flowering, the main plant will die, leaving the plants that formed around its base to replace it until they mature and the process repeats itself.

Our plant’s flower stalk was discovered bent over onto the greenhouse roof on July 22, 2019—most likely due to the previous night’s storm and the stalk weakening as the plant died. Greenhouse staff left the stalk on the roof to see whether some of the flowers would set seed.

The stalk and plant were removed on November 11, 2019. Greenhouse staff replaced the old plant with one of its shoots that had been divided from the parent plant and placed in a separate pot more than 16 years ago.