A single chocolate pod hides beneath the large evergreen leaves of its mother tree.

Native to South America and normally impossible to grow in the Sydney climate, the Theobroma cacao plant has a new home at the Royal Botanic Garden Sydney.

The plant is one of the star attractions in the Botanic Garden's new production glasshouse.

It is the first glasshouse in 90 years and is a stark contrast to its neighbouring stone greenhouses built in the early 1900s.

The high-tech production house has three chambers each with different climates where exotic and native plants will be grown for The Calyx, a horticultural display set to open in June.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 30 seconds 1 m 30 s Inside the Royal Botanic Garden glasshouse

The Calyx will house up to 18,000 plants to form the largest green wall in the southern hemisphere.

"It's totally for the wow factor," Dr Dale Dixon, curator manager of the Royal Botanic Garden, said.

"In this exhibition we're focusing on plants associated with the tropical parts of southern America so that's where chocolate is native to — really tropical conditions.

"We wouldn't usually be able to grow chocolate outside in Sydney."

Dr Dale Dixon shows off the single Theobroma cacao pod growing in the Royal Botanic Garden Sydney's new glasshouse. ( 702 ABC Sydney: Amanda Hoh )

The green wall will be six metres high and take up an area totalling 285 metres square.

Hundreds of species will be grown in the glasshouse including two other species of chocolate plants and rainforest plants such as flowering anthuriums, heliconias and various palms.

The New South Wales Government will spend $14 million to build The Calyx, while the glasshouse which cost $1 million, was funded by the Foundation and Friends of the Botanic Gardens.

Environment Minister Mark Speakman, who officially opened the glasshouse on Thursday, said The Calyx would be the one of the "world's greatest horticultural pavilions and a great addition to the Sydney tourist calendar".

The opening of The Calyx on June 11 will mark the Royal Botanic Garden's 200th birthday.