The fate of rare plants is in the sky – an Australian Oasis

Rare plants are finding space on a green roof in Melbourne, Australia. According to the New Scientist: ‘it’s a case of lofty living meeting Noah’s Ark’.

Rare plants are found on green roofs in Europe, especially Orchids. Here on this roof in Switzerland, the rare plants found their own way to the roof. However, a roof in Melbourne is taking the idea a step further by deliberately establishing a specific environment and planting to achieve an oasis for rare wildflowers.

rare plants - green roofs
Rare Orchids on a green roof in Switzerland

An oasis of rare plants in the sky

For the last six years, Australian conservationists have been growing critically-endangered native plants on the roofs of Melbourne. As is the case elsewhere, intensive agriculture has had an impact on regional wildflower plants. By planting the wildflowers on roofs, they are less prone to predation from invasive invertebrates. Furthermore, their seeds can spread more easily on the wind to surrounding areas at ground level.

Rain-irrigated volcanic soils

Green roof substrates are often created using volcanic material as they need to be light. In Melbourne, the soils were developed to match the growing conditions at ground level, the Victoria Plain being volcanic in character.

Water is an issue in Southern Australia, as it is elsewhere. So, once the plants had established, they were left to be irrigated naturally. This was to raise them to cope with local climate conditions.

Green roofs are an addition to conventional conservation measures

Not all the species grown on Melbourne’s roofs flourished – but some did. Obviously, green roofs are no replacement for conservation at ground level. However, if a few important plants can find sanctuary and potentially spread from the roofs, this can only be a good thing. As we have always said at, green roofs should always be about more than just stormwater and energy.

Biodiversity is a key benefit that should not be overlooked – and Melbourne is showing how it can be done in a new way.