14 June 2015 Last updated at 09:24 BST
Titan Arum produced a bud several weeks ago, which has recently been growing at several centimetres a day.
But up until Friday morning it had not been clear if it would produce a leaf, or a flower.
It will be the first time the so-called "corpse flower" has ever blossomed in Scotland.
It gets its name from the horrible stench it produces, to attract insects to pollinate it.
YOUR COMMENTS!
There were road works on my street and a lot of gas was coming through a broken pipe and it was so bad!
Many, Oldham, England
The worst thing that I have ever smelled was probably the French cheese that we sometimes get when we are on holiday there.
Martha
My sister was hoovering and then suddenly it stopped working and EXPLODED. It smelt very bad and me and my sister felt sick.
Cara, Melrose, Scotland
I found fox poo in my Grandma's garden and it was awful.
Rhiannon, Bolton, England
The worst thing I've ever smelt is a rat.
Kimya, England
Experts at the Royal Botanic Garden say one of the world's biggest - and smelliest - flowers is about to bloom in Edinburgh.