It might smell like a dead cane toad, but the blooming of what's affectionately known as the "corpse flower" is so momentous, people are prepared to fly several hours to witness it.
As staff at the Cairns Botanic Gardens last week monitored the progress of "Hannibal" – an Amorphophallus titanium, or titan arum, that had not opened since 2017 – one visitor booked flights from Brisbane to ensure they were there when it happened.
The plants are famous for the distinctive odour they emit into the air – a trait that has evolved to assist with pollination, by imitating the smell of a dead animal to attract carrion flies.
Cairns Botanic Gardens curator Charles Clarke estimates about 2,000 people have walked through the gates since since the plant began blooming on Christmas Eve.
"Dead cane toads", "dead snakes" and "rotting fish" were the three most common phrases used by visitors to describe the scent, he said.
"It's funny because lot of people turn up and say, 'I can't smell anything' and that's because the odour pulses out of the flower, so you can't always smell it," he said.
"It's really funny watching the expressions on people's faces change as they get a whiff."
'Can't be taken for granted'
Predicting when a titan arum will bloom is tricky, as they often struggle with bacterial and fungal diseases.
Dr Clarke said a series of false starts at the Cairns Botanic Gardens meant until late November there were no expectations Hannibal would bloom this year.
He said some people, including a visitor from Brisbane, travelled to Far North Queensland just to witness it.
"Going for a few years without [a bloom] seems to have reminded people this isn't something that can ever be taken for granted," Dr Clarke said.
"So it's really nice to see people are prepared to put that effort in."
By lunchtime on Boxing Day, the flower had already begun to collapse.
Dr Clarke said it would take until after Easter for staff to know enough about the plant's health to predict "to the nearest couple of years" when it might flower again.
Not alone in bloom
Some Amorphophalli will go through an entire life cycle in three or four years, although a titan arum can be expected to live for several decades.
The titan arum stores energy in its corm, or underground stem, by producing leaves and will only bloom when it has enough energy to do so.
This year produced a double treat for botanists in Cairns, as alongside the titan arum, a much smaller but rarer Amorphophallus discophorus also flowered.
"It only occurs on one mountain in central Java, so that's a very restricted range," Dr Clarke said.
"Having said that, it's actually a very easy species to grow.
"It seems to be quite well adapted to the climate we have in Cairns because, like southern Java, northern Queensland has a strong dry season and they seem to quite like that."
