How do you plan the management and maintenance of a green infrastructure asset when there is little to no information available about how different green infrastructure systems and plants behave on roofs and walls in your area?
This was the challenge that faced the horticultural team at the Adelaide Zoo when they first began installing green infrastructure 10 years ago. It’s a challenge they have overcome, demonstrated by the two green walls and five green roofs the zoo now boasts.
When the horticulture team first began installing green infrastructure, there were few examples of green infrastructure in Adelaide they could look to for guidance on what works and what doesn’t, or on how to successfully manage and maintain them.
Adelaide is in a warm temperate climate zone, with its own native flora and fauna that has adapted over many millennia to suit the unique conditions of Adelaide. For most of the zoo’s green infrastructure, the horticultural team were able to plant species that they had propagated in their own nursery. They knew these plants worked in their conditions on the ground. In some cases, they were also able to test how different plant species performed in different green infrastructure systems, also at ground level. The greatest unknown was how these plants would adapt to the conditions of a green wall or green roof with differences in wind, exposure, water availability and temperature.
The horticulture team therefore adopted an adaptive management approach to maintaining their green infrastructure. By monitoring plant growth and site conditions, they were able to adjust their maintenance accordingly. Monitoring plant growth allowed them to identify which species were not able to establish themselves and to replace them with species that thrived. For example, the team replaced lomandra which were struggling on a south facing green wall with elkhorns.
Monitoring also helped them to determine a watering regime that best suits the plants, and adjust artificial lighting for an internal green wall.
The horticultural team adapted their expectations of the layout of plantings to suit the natural conditions.
Another key component leading to the success of these green roofs and walls is that the zoo dedicates considerable staff time to ensuring they are well maintained. This is because landscape plays such an important role in providing an appropriate home for the animals, and a visually appealing setting for visitors. Furthermore, the zoo’s mission is to save species from extinction and connect people with nature. The horticultural team is responsible for landscaping and maintaining all exhibits, displays and gardens within the zoo, including green infrastructure, to align with this mission.
With green infrastructure that is still thriving 10 years on, the Adelaide Zoo demonstrates that a lack of green infrastructure in your area doesn’t meant that green infrastructure is not feasible in or suitable for your area. It demonstrates that you can achieve quality green infrastructure despite a range of unknowns, when you are responsive to your site conditions and adapt your management and maintenance to suit these.