Cities around the world are investing hundreds of millions of dollars in urban green spaces. Urban greening has wide-ranging benefits for human health and well-being, local and regional biodiversity, pollution mitigation, and local urban microclimate. However, maintaining vegetation in urban environments is expensive, which leads to overly simple plantings that have limited visual appeal and physiological resilience. We have recently developed a new approach to urban greening using Australian shrublands as a template. These “woody meadows” have high aesthetic appeal (e.g., year-round visual interest) and can be coppiced (removal of aboveground biomass every 2-4 years) to reinvigorate them. However, the success of woody meadows will depend on their ability to resist drought stress in unirrigated urban landscapes. Therefore, our overarching goal is to develop the necessary physiological understanding of Australian shrub species to create resilient, management-friendly woody meadows to enhance green spaces. In order to improve methods for selecting drought-tolerant shrubs, we investigated relationships between drought tolerance (iso-anisohydry and turgor loss point) and climate of origin for 24 Australian shrub species in a common-garden experiment. We also investigated how coppicing influenced drought resistance. We hypothesised that shrubs from hotter and drier climates of origin would be more drought tolerant (anisohydric) and have lower turgor loss points.
Results/Conclusions
All shrubs were able to resprout after coppicing and most species were anisohydric. Plant resistance to drought stress, as measured with turgor loss point, differed between newly coppiced plants (spring) and older shoots (summer). Relationships between drought tolerance and climate of origin were inconsistent and depended on the measure of iso-anisohydry used. Leaf water potential at the turgor loss point was not related to a species’ climate of origin or degree of iso-anisohydry. These results indicate that shrub species from wetter environments are equally suitable for woody meadows and that the turgor loss point is not a useful trait for plant selection. Woody meadows are a novel approach to designing low maintenance landscapes in cities. Understanding the physiological responses of shrubs to coppicing and summer drought is the first step in designing multi-species meadows for Australian cities. However, while we are designing these plantings for Australian cities, the approach is internationally applicable as natural shrublands occur globally and these species could be used as new templates for urban greening.