Carolus, one of Cornell’s two Titan arum plants, also known as “corpse flowers,” will again unleash its fetid odor in the Liberty Hyde Bailey Conservatory on Tower Road in the coming days.

Credit: Allison Usavage/Cornell University

“The flowering is brief – just a day or two – and difficult to predict,” said Paul Cooper, the Cornell University Agricultural Experiment Station greenhouse grower who cares for the Titan arums and more than 600 other species of plants in the conservatory. “But the bloom is nothing if not memorable.”

That’s because the Titan arum (Amorphophallus titanum) – native to the jungles of Sumatra, where it is threatened by habitat loss – has a fascinating pollination strategy: It releases volatile chemicals that smell like a rotting carcass to attract flies and carrion beetles to transport pollen from one plant to another.

The plant also warms to more than 100 degrees, to help waft the foul scent up into the canopy so it can travel far and wide. Skunk cabbage, a related plant native to the Finger Lakes, uses a similar strategy when it flowers in early spring, often melting surrounding snow.

Titan arums also produce the tallest unbranched flowering structure in the plant world, towering higher than 108 inches (9 feet). The last time Carolus flowered, it reached 75 inches tall; as of Sept. 11, it already stood 88 inches – making it the tallest Titan arum ever grown at Cornell – and was growing about five inches a day.

This will be only the second time since 2012 – when Carolus’ sibling, Wee Stinky, was the first Titan arum to flower at Cornell – that the plants have bloomed while students are on campus.

“They’ve been pretty bashful,” Cooper said. “This is the seventh bloom we’ve had, but it seems like they’re always flowering during breaks. We hope the students will take advantage of this opportunity to come to the conservatory to experience it firsthand.”

Titan arum flowerings were relatively rare at the time of that first flowering, which attracted more than 10,000 visitors who stood in line for an hour or more to catch a glimpse – and get a whiff. But since then, the species has become popular in conservatories around the world.

During that first flowering, Wee Stinky was pollinated by hand with pollen provided by Binghamton University, and Cooper distributed dozens of the resulting seeds and seedlings. The plants usually take seven to 10 years to reach flowering size.

Between flowerings, Titan arums produce a single towering leaf the size of a small tree. While Carolus blooms this month, Wee Stinky is in full leaf alongside it. The leaf gathers energy from the sun to refuel the corm – the underground bulb-like structure – to power the next flowering. Carolus’ corm weighed about 120 pounds when Cooper repotted it in July.

Since they reached maturity, Cooper has been able to coax each plant to bloom about every two years or so. The last time Carolus flowered, its timing was perfect and Cooper planted the corm outside in a pot in nearby Minns Garden. That was perhaps the farthest north a Titan arum has bloomed unprotected from the elements.

The conservatory is open to the public weekdays from 10 a.m. to 3 p.m., but will be open later during Titan arum’s bloom. Announcements related to Titan arum’s bloom – which will likely occur in the late afternoon and into the evening – can be found on the Conservatory blog or through Cornell’s College of Agriculture and Life Sciences (CALS) Twitter feed and Facebook page about extended visiting hours the night of the bloom.

Craig Cramer is a communications specialist in the School of Integrative Plant Science.