Now the energetic florist duo of Moxom and Whitney have focused their fashionable eyes on the terrarium, causing something of a craze throughout the city.

When Lou Moxom and Belinda Whitney took a gamble on starting up a tiny florist shop in Lonsdale Street in Braddon in 2012, they had no idea their particular take on botanical arrangements would cause such a stir.

They now have eight staff, have catered for royalty – they did the flowers at parliament for the visit of Prince William and the Kate Middleton last year – and have moved into a new shop in the Ori Building on the other side of Lonsdale Street.

Their ethos not to "overwork" arrangements, and to source many of their blooms from their inner-north backyards, has gathered them a loyal clientele and the enthusiastic embrace of the interwebs.

Their terrarium trade is also booming.

Last week, the pair ran their first terrarium masterclass – taking 10 people through the process of creating a mini-garden in a jar.

Now the waiting list has stretched to May, two extra classes have been put on and the orders for terrariums just keep coming.

What seems to set Moxom and Whitney's terrariums apart are the tiny figurines, sourced from the United States, that are set into the botanical scenes. They range from minuscule humans in various states of activity – hiking, swimming or reading a book on a park bench – to meerkats peeking over logs.

"We create imaginariums," said Ms Moxom.

She believed the current fascination with terrariums was a throwback to the 1970s, when the grooviest homes had gardens under glass.

"Lots of us grew up with them and remember mum and dad having them around. And we used to spend hours peering through the glass and imagining entire new worlds."

The modern incarnations provide for adults the same level of escapism that dolls and Lego do for children, she suggested.

But the creation of independent ecosystems may not be as simple as throwing a wad of backyard moss and a succulent in a bottle.

Whitney says there is a science behind creating a happy terrarium. Moss needs to be a specific type that doesn't require so much water as to harm the other plants.

"Our No 1 biggest problem is people tend to overwater," she said.

There also needed to be sufficient layers of rock and soil to sustain the plants. Every new terrarium owner gets a long list of instructions and troubleshooting ideas, and those who do the two-and-a-half-hour masterclass are given plenty of practical advice.

If it all turns to compost, Moxom and Whitney is quick to offer assistance.

"We do offer terrarium daycare and, in dire cases, hospitalisation. We can rebuild!" said Moxom.

To book the extra masterclasses call: 04777888805