New residential perennial floras reflect distinctive decisions of residential developers and new homeowners

Urban patterns reflect the people who build and manage urban space. However, most field research on residential vegetation focuses on household or neighborhood preferences, norms, or socioeconomic drivers of observed patterns and plant traits. Very few urban ecology researchers have studied residential real estate developers, who configure the space and establish the initial plant communities. How do the landscaping decisions of developers and homeowners shape residential perennial floras? To answer this question, I collected a stratified random sample of perennials at 60 newly built and sold homes in the Seattle, WA area. Through field sampling, conversations with new homeowners, and archival research, I assigned each individual perennial to one of three origins: remnant, planted by developers, or planted by homeowners. After describing landscaping decisions using plant traits (as presented in gardening literature), I evaluated whether planting decisions of developers and homeowners were heterogeneous and whether urban form or economic drivers influenced planted species richness. I also tested whether homeowner yard and plant buying preferences could be linked to planted richness. Given that developers and homeowners have different incentives, I hypothesized that they would choose different types of perennials and that urban metrics related to area and economics would increase species richness. I also predicted that homeowner preferences would be linked to species richness patterns. Developers planted most of the trees, shrubs, and graminoids. Homeowners planted fewer woody and more herbaceous perennial species. Parcel planting area, wealth related metrics, and parcel density increased species richness for some perennials. However, homeowner preferences were stronger predictors of their planting behavior than urban metrics. Because assembly of residential perennial flora communities is heterogeneous, future investigations in other urban ecosystems should incorporate preferences of developers and homeowners, site-specific constraints, and broader scale influences. More work is needed to understand developer incentives and preferences.