Some of us peak at 20. For one 80-plus-year-old American agave getting ready to bloom at Matthaei Botanical Gardens, adolescence is just beginning.

A variegated American agave collected in Mexico in 1934 by U-M grad student Alfred Whiting is sporting a flower stalk that grows nearly 6 inches a day. At full height the stalk may reach 20 feet or more and graze the glass ceiling of the conservatory.

That’s the good news.

The bad news — especially for anyone who’s seen this enormous plant in the conservatory or in nature with its sinuous yellow-streaked leaves bristling with spikes — is that the plant will bloom, set seed and die, says Mike Palmer, horticulture manager at Matthaei Botanical Gardens & Nichols Arboretum.

The American agave usually blooms in nature at 10 to 25 years of age, Palmer says. “Although no one knows for sure what combination of environmental conditions induces flowering. And it’s rare for one to bloom indoors.”

American agave foliage is usually 3 to 6 feet tall and 6 to 10 feet wide. The flower stalk can reach up to 30 feet. The American agave is often referred to as the “century plant,” probably because humans have noticed (and then exaggerated) how long it takes the plant to mature and flower.

Thankfully, life will go on for the Botanical Gardens’ variegated agave, Palmer points out.

“While it’s sad that the parent plant will die, it also grows ‘pups’ on the flower stalk and offsets at the base that are identical clones of the original plant,” he says. And it produces hundreds or even thousands of seeds that have the potential to grow.

“But in the harsh, low-water environment of the desert, plants must produce many offspring to get a few progeny that will reach adulthood,” Palme explains.

As for when the plant will actually flower, Palmer says it will probably be two more weeks before that happens.

“We still have a way to go before we see flowers,” he says. “So it’s impossible to predict an exact date.” When it does reach the ceiling, Palmer adds, staff will remove a pane or two of glass so that the stalk can continue to grow.

The Matthaei Botanical Gardens’ agave is native to the southwest United States and Mexico and is an example of a plant species that’s well adapted to dry or desert conditions. The American agave is now planted throughout the world as an ornamental in arid regions. It was likely planted in the ground bed of the conservatory on Dixboro Road in the early years of U-M’s botanical gardens at that location.

The American agave’s flower stalk looks like a giant asparagus spear, and in fact the plant is in the asparagus family. While many know agave as the source of tequila, the fiery distilled beverage is made only from the tequila agave.

In areas of Mexico where tequila is produced, the American agave is used to make a similar alcoholic drink called mezcal. The flower stalk of the American agave can be cut before flowering to produce aguamiel, a sweet liquid collected at the base of the stalk. This liquid can be fermented to make a drink called pulque.

Additionally, fibers gathered from within the leaves are used for making rope or twine.

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