It’s that time of year when Philadelphia row home owners with a green thumb fastidiously attend to their window boxes – selecting new plants to design an artful blend of colors, shapes and textures.

Sonja Dümpelmann is a historian of landscapes and the built environment who lived in Philly from 2019 to 2023. During this time, she researched how female reformers and activists in Philadelphia in the 19th and 20th centuries tended to window-box gardens both for charity and to spur urban renewal in rundown neighborhoods.

Dümpelmann recently published an article on this history in the architectural journal Buildings & Landscapes. She spoke with The Conversation U.S. about what she learned.

When I first moved to Philadelphia from Cambridge, Massachusetts, in August 2019, I was immediately struck by the window boxes. The lushness and freshness of the plants in many of the boxes, and sometimes in sidewalk planters, made walking more pleasant and interesting. This was especially the case in the hot summer months when I would often see plants from subtropical and tropical climates in the Rittenhouse Square, Fitler Square and Graduate Hospital neighborhoods.

I noticed that there were three categories of window boxes. Many were visibly cared for, often freshly planted and decorated several times a year in accordance with the changing seasons. Some were derelict and had spontaneous growth of saplings and different grasses. And a third category were boxes outfitted with plastic plants, perhaps signaling absentee owners or landlords who seek to simulate care.

Window boxes – especially the planted boxes, but also painted boxes that are empty – change outdoor space and building exteriors. They make them more colorful........

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