It took around 15 years for the corpse flower at the Australian National Botanic Gardens to flower for the first time. (ABC News: Penny Travers)
In short:
An Amorphophallus titanum or titan arum, commonly known as the corpse flower, has bloomed at the Australian National Botanic Gardens in Canberra for the first time.
The 15-year-old plant started unfurling its 135 centimetre-tall flower spike on Saturday afternoon, emanating a putrid stench described by some as smelling like "dead rat".
What's next:
The bloom is expected to start collapsing by Monday afternoon and will gradually return to a dormant state as an underground corm.
A rare flower that smells like rotting flesh is blooming for the first time at the Australian National Botanic Gardens (ANBG) in Canberra.
The Amorphophallus titanum or titan arum, commonly known as the corpse flower, produces the world's biggest — and smelliest — flower spike, or inflorescence, once every few years.
The one in Canberra started unfurling on Saturday afternoon, with a putrid stench emanating from its 135 centimetre-tall flower spike.
ANBG acting nursery manager Carol Dale said it usually took corpse flowers seven to 10 years to bloom for the first time.
"We've had this plant for approximately 15 years and it has never flowered so this is a first time for us," she said.
"We didn't think we had the right conditions to get it to flower stage and this plant just keeps surprising us."
The corpse flower started blooming on Saturday at around 1:30pm. (ABC News: Joel Wilson)
The bloom heats up, known as thermogenesis, and produces an intense stench of rotting meat to attract insects like carrion beetles and flies that pollinate the plant.
"It started smelling like wet laundry, dirty socks, dead rat, then we moved up to dead possum, dead cow, dead sheep, port-a-loo, bin hopper, things like that," Ms Dale said.
"As the humidity increases and the temperature, it's certainly more intense.
"It's a very beautiful and spectacular plant but the smell is very pungent."
Carol Dale says ANGB staff were taken by surprise. (ABC News: Joel Wilson)
Visitors to the gardens on Sunday described the smell as "damp socks", "Dynamic Lifter fertiliser", "rotten eggs", "rotten garbage" and "nightclub toilets at the end of a Saturday night".
Flower spike fast growing
The emergence of the flower spike took ANBG staff by surprise, with the plant coming out of dormancy earlier than usual and going "from nothing to producing a flower in the space of six weeks".
The 15-year-old plant unfurled its 135 centimetre-tall flower spike on Saturday afternoon. (Supplied: ANBG)
When the spike first emerged on New Year's Eve, it was thought that the plant was entering another leaf cycle.
It grew very quickly, and at some points was growing 6 centimetres a day, but it was only 12 days ago that staff confirmed the spike was actually a flower.
"It flowered a bit earlier than we were expecting, too," Ms Dale said.
"We were all predicting Tuesday to Thursday next week and it jumped the gun on us and started opening about midday yesterday and opened up over the course of the evening."
Staff at the gardens are monitoring the temperature of the corpse flower with an infrared camera. (ABC News: Joel Wilson)
Tickets snapped up fast
The ANBG released just 870 free tickets late Saturday for people to view and smell the Canberra flower on Sunday and Monday.
The tickets were snapped up quickly, and the gardens released another wave of 120 tickets, but they too were all gone before Sunday lunchtime.
Around 1,000 people secured tickets to see the corpse flower over Sunday and Monday.
Helen McHugh, the gardens' visitor experience manager, said where the plant was housed made it difficult to have large crowds through.
"It's not in a space that the public can go into, it's not a publicly-accessible area," she said.
"We don't have the right kind of conditions for it to have lots of people go through so we had to limit tickets … to look after this plant and the other plants around it in the tropical glasshouse."
Visitors of all ages enjoyed a rare glimpse of the corpse flower in Canberra. (ABC News: Joel Wilson)
The unfurling comes just a few weeks after Sydney's famous corpse flower Putricia bloomed, drawing a crowd of almost 20,000 people and more than a million views on its YouTube live stream.
A second flower is currently blooming at the Sydney Botanic Gardens but will not be displayed to the public and instead be kept in the nursery to better control conditions.
Ms McHugh said there were no plans to name Canberra's corpse flower.
Global conservation efforts
Corpse flowers are rare and endangered and usually found in the West Sumatran rainforests, with estimates that there are fewer than 1,000 specimens left in the wild.
How much did Putricia smell like a corpse?
Photo shows Crowds of people hold their nose while they look on at a large flower blooming inside a tent.
They thrive in shady, moist and warm conditions at about 22 degrees Celsius and 75 per cent humidity, and only produce a single leaf or a single flower spike at a time, going dormant between each cycle.
Canberra's plant had been through a number of leaf cycles during its 15 years but had never flowered before now.
It is part of a global conservation program but the current flower spike has not been pollinated and won't produce any fruit and, subsequently, seeds.
The smell, along with the colour of the spathe, trick pollinators into thinking it's rotting flesh. (ABC News: Joel Wilson)
The flower spike, made up of the spathe and spadix, contains a collection of hundreds of separate male and female flowers and is not self-pollinating.
"First the female flower matures and that's when the heat and the smell comes and insects are all attracted, and then the male flowers mature producing the pollen, and that gets carried off to other flowers," McHugh said.
"But unfortunately we've only got one here.
"You need to have pollen from another plant … [because] the female flowers are past their prime before the pollen is ready."
A fly lands on the corpse flower's spadix after being attracted by the smell. (ABC News: Joel Wilson)
But Ms McHugh said the pollen from Canberra's flower would be "collected, frozen and sent off to fertilise another flower elsewhere".
After two to three days, Canberra's flower spike will collapse and gradually die back completely. The plant will then be dormant as an underground corm for about six months before a new leaf or flower spike emerges.
"We cover the pot, and have a big sign next to it saying "do not water" because this dormant stage is when it would be dry season in tropical areas and, in our kind of environment, adding water could rot the corm," Ms McHugh said.
"We have to be patient then. It looks like the plant is dead, but really it's just sleeping and we have to wait for an emergence.
"You'll then see a little tiny spike coming up, and the spike at first, for a leaf or a flower, looks exactly the same."
Visitors were streaming in to see and smell the corpse flower on Sunday. (ABC News: Joel Wilson)