Do natural phenomena count as urban ephemera? Spring and autumn colours; swallows, swifts and martins; the occasional cry of a gull or jackdaw. What is the lifespan of ephemera? A day, a month, a season, a year? Maybe it defies definition or at least depends on your starting point.
So, “Urban ephemera are organized, momentary, repeated urban public presentations. They include parades, festivals, celebrations, outdoor performances, and rituals of all kinds. Because they impress themselves upon the public images of cities in small ways and large, Mark Schuster, a cultural policy analyst, urges city designers and planners to add ephemera planning to their list of tools.” http://culturalpolicy.uchicago.edu/papers/workingpapers/schuster.html
Photo: Plane tree, Ipswich, April 2012