I love garden 'before and after' photos. They can be just as fun for me as apartment redesign photos. The Horticulture Society of New York, a non-profit that is over a century old, is responsibe for creating (and maintaining) gardens in a number of public libraries in NY's boroughs.
They also have a fantastic blog written by their Director of Horticulture, Alex Feleppa.
Flatbush branch before
Flatbush branch after
Dekalb branch before
Dekalb branch after
To see the other branches the society has helped take a look at photos of their projects here.
The society is also a great resource for anyone in the city who needs help with plant or garden questions.
The blog is, seriously, great. Alex Feleppa is a recent grad of the NYBG Hortculture program - his posts are thorough and you can tell he's excited about what he does. The blog, which is all about plants in the NYC area, is a resourceful archive of his daily travels, HSNY events, and questions posed to the HSNY about plants. Thanks Alex!
matt at apartment therapy dot com