Cambridge University Botanic Garden has revealed what it calls a "special gift" to plant enthusiasts - and it's a "total stinker".
Visitors will know they are close to the orchid bulbophyllum phalaenopsis when they start to smell the "delicate aroma of rotting cabbages", the garden's Facebook page says.
"The odour has also been described as smelling like dead rats decomposing next to rotting fish.
"To the carrion flies and beetles that pollinate it in the wild, it smells amazing."
The orchid was collected from Papua New Guinea and is rarely seen flowering outside its natural habitat.
The botanic garden said it was flourishing thanks to the care of its volunteer orchid expert Phil.
"Our glasshouse team think it will reach its ponging peak any time soon," they said.
"Only time will tell if it's in time for Halloween but we can confirm if you get nice and close to it now, you won't be disappointed!"
Plants and flowers that smell bad usually do so to attract insects and flies that normally leg their eggs in faeces and rotting materials.
Attracting by the stench, they end up pollinating them before leaving.