A giant bud is about to unleash one of nature's foulest, fastest, and most elusive spectacles in London

The rare and infamous titan arum (Amorphophallus titanum) may be just days away from opening inside of the Princess of Wales Conservatory, Kew Gardens' horticulturists have said. Known to many as the "corpse flower" due to its unmistakable stench of rotting meat, it is the first of Kew's impressive titan arum collection to flower at the West London botanical garden this year.

Solene Dequiret, Princess of Wales Conservatory Manager, said, "It's really hard to tell exactly when a titan arum will flower and they always keep us guessing until the very last minute, but we are confident it is a matter of days before this specimen opens.

"We have been looking after the plant for a few weeks now, and it is now growing at an incredible pace of about 8 cm a day.

"The bud now measures more than 2 m 20 cm in height, so we're all getting ready for the smelly spectacle to start. You can feel the excitement in the air!"

The plant's bud, no more than 66 cm tall, was moved into the glasshouse's climate-controlled tropical zone on 4 April, where it has been carefully monitored and measured each day in anticipation of its inflorescence (flowering structure) opening.

A fleeting rainforest giant at Kew

Native to the rainforests of Sumatra, the titan arum is as impressive as it is unpredictable, as it takes many years for these plants to reach maturity and flowering size. When the bloom opens, it is fleeting, lasting 48 to 72 hours. It is incredibly hard to predict just when this might happen, even in cultivation.

Visitors keen to catch the plant in the act are invited to follow Kew's social media channels on Instagram and Facebook, which are already sharing regular updates and will be the first platforms to break the news.

When it flowers, the titan arum creates one of the biggest inflorescences in the world, measuring up to 3 m in height. But it is best known for the incredible stench it releases in the process, which is an evolutionary adaptation meant to attract carrion flies and other pollinators.

When it blooms, the spadix, or central structure, also produces heat, which helps the plant to disperse its rotting stench far and wide through the rainforest.

Tom Pickering, Head of Glasshouses Collections, said, "Simply put, there is no avoiding the titan arum once it has opened! The moment you set foot into the glasshouse, its unmistakable stench hits you right in the face and overwhelms your senses.

"And yet, despite this formidable feature, it is easily one of our most popular visitor attractions."

Behind-the-scenes care and conservation

Hidden away behind the scenes and from the public's eye in Kew's Tropical Nurseries are about 40 titan arum specimens of varying sizes and ages, most of which were donated as seed from the Botanic Garden at the University of Bonn in Germany.

The plant grows best in moist, humus-rich soil and temperatures of about 22°C and 75% humidity.

Because it is rare to have more than one titan arum flowering at the same time—though last year saw several flowering in rapid succession—Kew's horticulturists will often manually collect the plant's pollen and freeze it until another one blooms.

And far from just being a popular attraction, Kew's collection of titan arums serves an important conservation purpose as well. Sadly, in the wild, the titan arum has been assessed as Endangered on the IUCN Red List of Threatened Species. It is mostly under threat from deforestation and land use change, as its habitat is logged for timber and oil palm plantations.

Botanic gardens such as Kew play an important role in conserving such threatened plants outside of their native habitats, known as ex situ conservation, while helping to raise the profile of plants and fungi as the important cornerstones of our livelihoods.

Because the titan arum's seeds are recalcitrant, they cannot be dried and stored in the Millennium Seed Bank at Kew Wakehurst, meaning it is best conserved through cultivation in living collections like those at Kew.

Tom Pickering said, "The titan arum is a fine example of how botanic gardens play an important role in conserving endangered plant species ex-situ in living collections.

"By cultivating, propagating and distributing plants within a community of botanic gardens, we can help to conserve threatened species so that they survive despite uncertain futures."

A long history of titan arums

There are more than 240 species in the genus Amorphophallus, spread from Tropical and South Africa, Madagascar, Tropical and Subtropical Asia to North Australia. Of these, A. titanum is easily the most popular one due to its impressive size.

The first ever titan arum to flower at Kew Gardens, and indeed outside of Sumatra, was 135 years ago in 1889. Its second bloom in 1926 proved so popular that the police had to intervene to keep the crowds under control.