On top of QT Melbourne on Russell Street is a secret garden. Originally it was a source of produce for the hotel’s food and beverage team, but last year it was opened up as an intimate function and event space. Now QT is teaming up with specialist Yarra Valley gin distillery Four Pillars to turn the compact rooftop garden into a summer bar hideaway called The Secret Garden Bar.

Enter via the laneway beside the hotel, where you’ll find a staff service entrance with an elevator that’ll take you to the restaurant kitchen before you finally arrive at your destination. In the garden you’ll find a mural by local artist Ry Wilkin inspired by the 18th-century gin craze, as well as planter boxes full of herbs, fruits and vegetables – many of which end up in cocktails specifically designed for the bar. “Having a garden element, and gin, and springtime, it just all kind of made sense,” says James Irvine, creative director of gin drinks at Four Pillars.

The cocktail list is, unsurprisingly, gin-inspired, with specials such as the Passion Killa, made with sour passionfruit-infused Four Pillars Bloody Shiraz Gin and mixed with Strangelove’s Bitter Lemon Tonic and lime leaf. Or there’s the Wild Strawberries, which uses the garden’s wild strawberries and coriander, Four Pillars’s Rare Dry Gin, and Regal Rouge’s Wild Rosé vermouth. Irvine is most excited about the Gin Spritz, which has three types of stone fruit carbonated with ginger leaf and lemon myrtle.

Four Pillars has created a small-batch gin exclusively for The Secret Garden Bar (it has a hint of savouriness, distinguishing it from the distillery’s other tipples), which is designed to work with all the produce on the roof. “It’s a beautiful balance of citrus and spice,” says Irvine. “We’re talking red Szechuan, whole Tasmanian pepperberries (instead of the leaves), coriander, ginger and desert lime.” Customers are encouraged to try the gin and even to pick their own herbs to mix with their choice of gin.

The bar menu is designed by QT Melbourne’s executive chef Andy Harmer (formerly of Vue de Monde) and Four Pillars’s Made From Gin creative director Matt Wilkinson (Pope Joan, The Pie Shop). The two came up with a menu that combines the Made From Gin range of products with the garden’s produce. There are chipolatas and marmalade-glazed skewers made with meat from Four Pillars’s gin pigs (pure black Yarra Valley Berkshire pigs that are fed all the leftover botanicals from the distillery, except for the oranges – the jam-makers get those). There’s also kingfish cured in the Bloody Shiraz gin and a gin-chocolate fondue.

“It’s an unreal space,” says Irvine. “You can actually walk around and see where your produce is grown but you’re actually in a garden, which is hidden completely on this rooftop, so it really is a secret garden.”

The Secret Garden Bar at QT Melbourne opens on October 24. It will be open from 5pm until late every Thursday and Friday until the end of summer.