Indonesia’s Sumatran rainforests are home to a number of unusual plants and animals. Orangutans, sun bears, clouded leopards and Sumatran rhinos are all found there. But one of the strangest things in this especially humid landscape might just be the titan arum, the largest inflorescence plant in the world that’s more commonly known as the “corpse flower”.

This plant is endemic to the Sumatran rainforest and only blooms every five to seven years. But half a world away, a corpse flower in Stellenbosch is expected to bloom over the weekend. This is according to Donovan Kirkwood, curator at the Stellenbosch University Botanical Garden.

“This is the first time [this plant] is flowering and it will probably grow to two and a half metres,” says Kirkwood. This titan arum is still relatively young but when fully mature they can grow up to 3m, he adds. 

The titan arum is expected to bloom between Sunday, 11 December and Tuesday, 13 December and daily updates are being posted on Instagram to track its progress. 

A smelly flower

“The titan arum is unique because it is the largest single inflorescence of any plant in the world,” says Kirkwood. An inflorescence is when many tiny flowers cluster together on a plant, and in the arum family this is on the central spike or spadix.

There are a “bunch of girl flowers at the bottom and a section of boy flowers above that, with the tip of the spike devoted to being really stinky,” explains Kirkwood. 

But what makes the titan arum unique and gives it its nickname is how it has evolved to attract pollinators. 

“When it is flowering that spadix actually generates heat – it is one of the few plants that generates its own heat while it is growing,” says Kirkwood. 

The stench from the titan arum lasts two or three days. (Photo: Téa Bell)

This heat enables the plant to “emit a bunch of volatile organic compounds that smell like a deer carcass that’s been lying in the sun for four days”.

The plant only stinks when it is in bloom. “That stink will last for two to three days and it’s gonna be pretty powerful.”

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This smell evolved to attract flies that act as pollinators. Flies usually lay their eggs on the corpses of dead animals and the corpse flower’s smell mimics that odour, says Kirkwood.

“The flies get tricked into coming to this plant because they think it’s a dead animal but it’s actually just a smelly flower pretending to be a dead animal. 

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“You are not gonna want to stay and appreciate the beauty of the thing for too long.” But, the plant can be viewed in a greenhouse that is kept at 90% humidity and that can be as hot as 35°C in summer.

“And that’s a lot like the titan arum’s home in Indonesia – sweaty and tropical.”

Under threat

The titan arum is an International Union for Conservation of Nature (IUCN) red-listed species.

“Like almost every plant in the world, the primary cause of the titan arum being endangered is habitat loss,” says Kirkwood. The tropical forests have been cleared at a rate that is second only to the fynbos in the winelands.

“There is almost no habitat left, so the populations that would have once been extensive across that landscape are now down to a few small fragments and in need of conservation efforts.” 

Flies usually lay their eggs on the corpses of dead animals and the corpse flower’s smell mimics that odour. (Photo: Téa Bell)

While the Stellenbosch University Botanical Garden is not actively involved with the conservation of the titan arum, the plant on display is used to educate people about endangered plants, biodiversity and threats to wild habitats. 

“We have a very strong in-house conservation programme and we have around 60 South African plants that are on the brink of extinction,” says Kirkwoord. These plants are being bred to be put back in the wild or into other collections for the future, but currently the titan arum is not being worked with in the same way.

“It’s always nice to not think of these charismatic titan arums as the only things threatened by habitat loss in that landscape. It is a canary in a coal mine.” DM/OBP