Titan Arum

Alice is on Bloom Watch听

It has been said that everything that is three is perfect. We couldn鈥檛 agree more. Smaller in stature but just as powerful as her fellow corpse flowers, Alice the Amorphophallus is now on bloom watch. You can visit her at the Sensory Garden.听

Meanwhile, our beloved Spike is winding down from a spectacular bloom on June 15. Before Spike, Sumatra was the first to bloom this year on June 7. Both unleashed a stench that filled our Plant Science Center where they were on display.

The corpse flower (Amorphophallus titanum) is also known as the titan arum. In bloom, it听looks like a 6- to 8-foot-tall flower, but it鈥檚 actually a tall spadix (flower structure) wrapped by a spathe (a frilly modified leaf). Technically the largest unbranched inflorescence, or flowering structure, in the world, the titan arum also sends up tall, umbrella-like, individual leaves that can reach 15 feet and look like small trees.听

It鈥檚 huge underground, too: leaves and flowers are powered by the largest known corm (a type of tuber) in the world. To bloom, the arum's corm gets bigger than a beach ball鈥攕ome have been known to reach more than 200 pounds.

Titan arums are rare.

Corpse Flower Smell

Titan arums don鈥檛 flower often鈥攚hether in the wild or at botanic gardens.

A native of the equatorial rainforests on the island of Sumatra (in the Indonesian archipelago), Amorphophallus titanum takes its time to grow before blooming鈥攐ften ten years or more. Each year, the corm sends up a leaf to absorb energy from the sun. Finally the corm has enough energy stored to send up a flower bud and try to reproduce, and it鈥檚 worth the wait: an utterly thrilling visual phenomenon.

Our team has been nurturing titan arums since 2003.听

The titan arum bloom cycle is unpredictable.

At first, even the experts don鈥檛 know if what鈥檚 emerging is a leaf or a flower bud. Days must pass before the subtle signs鈥攁 more dimpled shape, a suggestion of a frill鈥攑oint to flowering. Soon the plant is powering up, growing 4 to 6 inches per day, and the spiky spadix can be seen rising from the ruffly spathe.

About two weeks into the process, growth slows, and the spathe begins to unfurl. Without warning, on a schedule of its own, the big event has begun.

Titan arums smell awful.

Corpse Flower Smell

Like many flowering plants, the titan arum uses scent to attract pollinators when it鈥檚 ready to reproduce.

Unlike most flowering plants, the arum has tremendous energy reserves that allow it to blast out its scent in one big, hours-long burst.

And the smell! The Indonesian name for the plant translates as 鈥渃orpse flower,鈥 an apt summary of the decaying, rancid, rotten stench. However, what smells horrid to humans is a magnet for the carrion beetles and flesh flies that are the titan arum鈥檚 natural pollinators.

The Big Night

The titan arum bloom cycle is fast, often beginning in mid-afternoon one day, and ending 24 to 36 hours later. As the spathe opens, the true female flowers at the base of the spadix signal their readiness for fertilization by releasing scent molecules. Internal heat volatilizes the molecules (turning them to vapor), and the resulting blast of stench alerts pollinators up to an acre away that the big night has begun. As the clock ticks off the hours, the spathe fully unveils its internal, deep maroon color鈥攁 meaty hue favored by the beetles and flies now crawling in, flying in, and gathering at the base of the 鈥渧ase.鈥

Bloom Timeline

Bustling about in the female flowers for the rotting flesh they want to lay their eggs on (hatching larvae feed on animal remains), the insects deposit pollen carried in on their backs and bodies from the last flower they visited鈥攖hereby completing the act of pollination that the entire evening is about.

By daybreak, the window of pollination opportunity is over, and the smell dissipates. Now it鈥檚 the male flowers鈥 turn to open, shedding fresh pollen on to the insects trapped inside. (Scientists think they鈥檙e trapped鈥攔esearch continues.) As the day goes by, the spathe closes and the entire inflorescence begins to crumple, setting the insects free and protecting the (hopefully) pollinated flowers inside.