Visitors are expected to flock to The Royal Botanic Gardens in Edinburgh (RBGE) at the peak of the plant's pungency over the next three days.
The giant Amorphophallus Titanum has a strong smell of rotting flesh.
Horticulturist Sadie Barber says she was ''thrilled to finally see and smell" the plant after "12 years of careful cultivation''.
The plant, which has the heaviest corm ever recorded (153.9kgs) has produced seven leaves in the 12 years that it has been at the garden, so horticulturists are "delighted to finally" have a flower.
Ms Barber, who was gifted the corm in 2003 by Hortus Botanicus in Leiden, Netherlands, said: "We are thrilled to finally see, and smell, this incredible curiosity of the plant world after 12 years of careful cultivation by the Horticulture team at RBGE.
"The spadix has so far reached an impressive height of 255cm and may even grow a few centimetres more in the next days.
"It really is one of the most extraordinary flowering plants we have ever seen, and great to think that something that grows naturally so far away can be enjoyed by visitors to the Garden here in Edinburgh.''

Catherine Seeley was subjected to the abuse after she was co-opted as a Sinn Féin councillor in Craigavon, County Armagh.
She thanked pupils at the Boys' Model School in the loyalist Ballysillan area for their "full support".
Ms Seeley was speaking at Sinn Fein's annual conference in Wexford.
She said: "In the past few weeks, in my role as a teacher, I have been subjected to a campaign of sectarian intimidation.
"I have already expressed my warm thanks to all who have offered me support, including family, friends, colleagues, educationalists and politicians from various parties.
"I want to take this opportunity to publicly send a message of gratitude to those pupils of the Boys' Model School in north Belfast who have courageously offered me their full support.
"They are a testimony to the values that should permeate not just education but every aspect of society.  They inspire hope and confidence in me for the future."
She added that her recent experience had shown "that students can be much wiser, more mature, more responsible and more respectful than some who claim to speak on their behalf".
Ms Seeley's decision to leave her post was announced on Friday in a joint statement by the school's board of governors and the Belfast Education and Library Board.
She is to move to another education board area.
The Protestant Coalition group had objected to her employment at the school.
It said her role at the school should be looked at because of her political views.
During his speech, the Deputy First Minister Martin McGuinness contrasted the response of Miss Seeley's pupils to that of some unionist politicians.
"If this situation was reversed and a young Protestant teacher who was also a member of the DUP was being forced from her job in a Catholic school, I would be at the door accompanying her to her work," he said.
Mr McGuinness also called on those he described as "sensible people within unionism" to use their influence to secure a deal on flags, parades and the past.
Sinn Féin President Gerry Adams told delegates during his address on Saturday evening that the issue of contentious Orange parades still needed to be resolved.
"While there may be obstacles, be sure of one thing - change will not be stopped," he said.
"I am happy to meet with the Orange Order at any time to discuss these matters.
"I want to see the Orange treating its Catholic neighbours with respect.
"I want to see it upholding law and order.
"The Orange Order of Ireland is one of our national traditions.
"And Sinn Féin wants all our traditions freed up from sectarianism from any quarter, to live together in peace and respect and with tolerance from everyone for everyone."
One of the world's largest and smelliest flowers has blossomed for the first time in Scotland.
[NEXT_CONCEPT]
The teacher who quit her job at a north Belfast school after being targeted by online sectarian abuse has spoken publicly for the first time.