However, while planting local species such as oakleaf hydrangea and ostrich fern may feel patriotic and green, Morris Arboretum director Paul Meyer notes that in an urban environment, most native plants simply cannot survive. When a native dogwood struggled to adapt to the city, Rutgers University scientists hybridized it with an Asian dogwood to create the locally thriving Rutgers dogwood.
In addition, many foreign species have become part of our environment, like the blossoming Japanese cherry trees at Fairmount Park. Landscape architect Alice Doering, who designed a native-plant garden in Fairmount Park with the Pennsylvania Horticultural Society, said that using native plants exclusively is difficult and restricting.
Moreover, while some affluent suburbs may have the time and resources to legislate landscaping, most towns probably have other priorities.
Rather than laws and mandates, the cause of native plants can be furthered more effectively by a better-informed public. Lawn grasses are largely nonnative, and they cover more than 90 percent of the suburban planting space in Pennsylvania, Delaware, and Maryland, according to research by Douglas Tallamy, the author of Bringing Nature Home. The Pennsylvania Horticultural Society, Morris Arboretum, and Bartram's Garden all provide programs on native plants that can help homeowners convert ecologically harmful, labor-intensive, monoculture lawns into more diverse gardens and meadows where local and foreign plants coexist.
Education about native plants can do more than xenophobic landscaping laws to help our flora flourish. Like the region's cosmopolitan population, plants from the four corners of the globe contribute to the rich fabric of the Philadelphia area.