Water availability can be a major abiotic constraint for plant success in urban areas. To ensure resilient green spaces, understanding which species are able to cope with low water availability is paramount for plant selection. However, in the horticultural industry, descriptions of species’ responses to low water availability are oftentimes poorly defined, inconsistent across sources, and informed from the natural habitat of species, personal experience, or both. Therefore, a method to objectively assess tolerances of species to low water availability is needed. Using a multivariate approach, we characterised the drought strategies of 113 horticultural plant species spanning five different growth forms (graminoids, herbs, climbers, shrubs and trees) by using five leaf-level traits (leaf mass per area (LMA), leaf thickness, unit leaf area, leaf dry matter content (LDMC) and leaf water potential at turgor loss point (TLP)). Based on this approach, we found that species clustered into three distinct groups, which correspond to fundamental drought strategies based on previous ecological literature (i.e., ‘dehydration avoiders’ (species with high LMA and LDMC, thick leaves and low (more negative) TLP), ‘dehydration tolerators’ (species with low LMA and LDMC and high (less negative) TLP) and an ‘intermediate’ mixture of the two strategies). We found that the majority of species that were considered as ‘drought tolerant’ by the horticultural industry were classified as either ‘dehydration tolerators’ (31.9 %) or ‘dehydration avoiders’ (42.5 %) using our trait-based approach. We did not find any strong connections between the climate of origin of our species and our trait-based classifications. Distinguishing between dehydration avoidance and dehydration tolerance may help to enhance horticultural guidelines by better informing which species are suitable for particular biophysical and landscape contexts. This trait-based approach allows for evidence-based evaluation of drought strategies of new and emerging species and cultivars that may be suitable for urban landscapes.

可用水可能是城市地区植物成功的主要非生物限制因素。为了确保有弹性的绿色空间，了解哪种植物能够应对水资源短缺的问题对于植物的选择至关重要。但是，在园艺业中，对物种对水资源匮乏的反应的描述通常定义不清，各来源之间不一致，而且是从物种的自然栖息地，个人经历或两者兼而有之的。因此，需要一种客观地评估物种对低水可利用性的耐受性的方法。我们使用多变量方法，通过使用五种叶面特征（每面积叶重（LMA），叶厚，单位叶面积 叶片干物质含量（LDMC）和在膨松损失点（TLP）的叶片水势）。基于这种方法，我们发现物种分为三个不同的组，这与基于先前生态学文献的基本干旱策略相对应（例如，“避免脱水”（LMA和LDMC高，叶片厚而TLP低（负性更高）的物种） ），“耐脱水剂”（LMA和LDMC较低且TLP较高（负值较低）的物种）和两种策略的“中间”混合物）。我们发现，使用基于特征的方法，园艺行业中大多数被认为是“耐旱”的物种被归类为“耐脱水剂”（31.9％）或“避免脱水剂”（42.5％）。我们没有发现我们物种的起源气候与我们基于特征的分类之间有任何紧密的联系。通过更好地告知哪些物种适合特定的生物物理和景观环境，在避免脱水和耐受脱水之间进行区分可能有助于增强园艺准则。这种基于特征的方法可以对可能适合城市景观的新物种和新品种的干旱策略进行基于证据的评估。