How air plants can work together to create much-needed city shade

The trouble with gardening on roofs often comes down to weight. There’s the load of the plants themselves, then there’s the growing medium in which they need to stretch their roots, plus the containers required to house them and the water to hydrate them.

It can take a lot of engineering to make a green roof, well, green. So, how convenient would it be to have a plant that can grow on top of buildings on nothing but thin air?

Lloyd Godman and Geoff Beech are showing that tillandsias will do just that. What’s more, these epiphytic bromeliads can provide shade, help combat pollution and offer a spikey, silvery, intermittently flowering visual appeal.

Having installed a handful of air plants on the 92nd level of Melbourne’s Eureka Tower nine years ago and monitored their steady growth since, Godman and Beech recently took matters a step further. In what they say might be a world first, they have fashioned a tillandsia-covered shade screen for the roof of a 10-storey city building.

Godman says its like shade cloth except there is “100 per cent no plastic”. He says all that this living screen needs by way of nourishment is to get rained on every now and then. This structure installed on Council House 2 (CH2) in Little Collins Street follows a thriving vertical one that they installed late last year on the same property. The building is owned by the City of Melbourne and has been a testing ground for environmentally sustainable initiatives ever since it was completed in 2006.

Godman and Beech say these tillandsia structures are a “sustainable way of creating shade in the city” and, on a roof, require less maintenance than climbers trained over trellis or trees. Each individual air plant is attached with wire to a metal frame and largely left to do its own thing. Although, in years to come, the plants will need to be thinned out to accommodate their growth.

While the new horizontal screen is already casting dappled shade over a CH2 staff seating area, the shade will only get denser as the tillandsias flower, produce “pups” and spread. While the four different types of air plant used on the screen won’t tolerate frost, they can stand up to cold weather, extreme heat and lacerating winds.

Because these plants – Tillandsia ‘Houston’, Tillandsia bergeri, Tillandsia paleacea and Tillandsia usneoides or Old Man’s Beard – flower at different times throughout the year, they offer lengthy seasonal interest. The blooms of Old Man’s Beard will offer fragrance to boot.