A biological experiment that aims to measure the viability of air plants at skyscraper heights is taking place atop Melbourne’s Eureka Tower.

Ecological artist Lloyd Godman is conducting the experiment, which sees a series of Tillandsia plants housed in cages installed on levels 56, 65, 91 and 92 of the 297-metre tall tower.

The Tillandsia plant’s low need for maintenance and positive environmental impact prompted Godman to observe its growth and resilience at one of the highest points in Australia’s built environment.

According to Godman, the experiment could be the highest-altitude plant installation in the skyscraper world. According to his research, the Marina Bay Sands in Singapore, at 55 storeys, is the current highest. That would make the Eureka 92-storey experiment a “significant step upwards,” he said.

Godman collaborated with environmental scientist Grant Harris and structural engineer Stuart Jones for the project. The trio aimed to demonstrate a new way of incorporating plants on high-rise buildings.

The experiment dovetails with the global movement toward rooftop and vertical gardens.

While architecture that implements greenery is growing in popularity, the costs associated with building and maintaining rooftop gardens or vertical gardens are not generally disclosed publicly. In fact, Godman noted that the cost to maintain a typical vertical garden is equivalent to approximately 20 per cent of its installation price per year. Those on skyscrapers often have to be replanted multiple times.

“Harris completed a recent study that found 97 per cent of vertical gardens will fail due to trying to sustain the cost of maintenance,” he explains. “They go up, they look fantastic, but they don’t work.”

Godman believes a vertical garden needs to perform sustainably, from the initial vegetation choice onward. Unlike most plants, the Tillandsia species doesn’t require soil to grow; the plants can absorb moisture through their leaves.

“It is also one of the few plants that will purify the city at night,” Godman said. “When the sun goes down, the pollution levels go sky high and the Tillandsisia will help to trap it. They photosynthesise at night, absorbing the carbon and heavy metals out of the atmosphere – a cactus does the same thing.”

plants at heights

Environmental scientist Grant Harris, ecological artist Lloyd Godman and structural engineer Stuart Jones.

The Tillandsia plant is part of the Bromeliad family and is considered sub-tropical. It is able to survive through drought conditions and requires less care than other plants, making it an ideal candidate for the climate at skyscraper heights.

Godman and his team took a series of the plants in wired cages and locked them down into four locations across the building. The cages are built from recycled mesh and while they are designed to protect the plants from being blown away, they also suit the Eureka tower’s architectural aesthetic. The tower features colour and design elements that reference the Eureka Stockade – a rebellion during the Victorian gold rush in 1954.

Godman said the cages are a reference to the only person imprisoned as a result of the Eureka Stockade, Henry Seekamp, editor of the Ballarat Times who was found guilty of seditious libel.

The experiment demonstrates the potential to remove the heavy load a vertical garden can place on a building.

“Air plants are so light,” Godman said. “They weigh only two to three kilograms a square metre while a typical vertical garden will house plants that can weight up to 60 to 70 kilograms per square metre.

The other benefit is that air plants can be suspended off a building by a distance of a metre or more. According to Godman, they make vertical gardens very versatile as the plants don’t need to sit directly on the building.

The experiment is expected to measure the performance of the plants over nine months to see it through a Melbourne summer and winter. The plants will be subjected to up to 200 kilometre per hour winds and extreme sunlight.

Godman has experimented with air plants in the past. Last year he launched “Airborne” as part of the Melbourne City Council 2013 Arts Grant.

Airborne was a unique series of super-sustainable rotating air gardens suspended high in the sky between existing poles at the Les Erdi Plaz, Northbank – the first in the world according to Godman.

Eight suspended air plants endured “Melbourne summer’s demanding hot dry conditions without any auxiliary water system and no soil medium,” Godman said. “Unlike typical vertical gardens, there is no maintenance other than to harvest the plants biannually to retain the desired form which offers a resource to create further living works.”

Godman noted that the right species of Tillandsia can withstand daily temperatures of up to 75 degrees with no water or soil.

The overall objective of Airborne was to demonstrate how plants can “occupy space rather than surface” – an objective Godman is keen to replicate across the urban built environment.

“We’d love to see Melbourne become the centre of air plants – they came from Melbourne. At the moment, we’re ahead of anywhere in the world, in terms of the research into these plants and their opportunity in the built environment,” he said.

Godman acknowledges that the Tillandsia may not necessarily earn points for looks – they sometimes die off quickly – but their hardiness makes them a good choice for sky-high greenery nonetheless.

“You need to take into account that any plant you put into the urban environment on a building, at some point, the foliage will die,” he said. “If it grows quickly, it will die quickly but Tillandsias will just grow over the top of the old one.”