The USA National Phenology Network (USA-NPN) engages volunteer observers to collect phenology observations of plants and animals using consistent standards and to contribute to the USA-NPN National Phenology Database. In March 2009, the USA-NPN National Coordinating Office implemented an online monitoring program for 213 plant species.

In this pilot year of the program, 547 observers reported phenology observations on one or more plants via an online interface. There was substantial national interest in participating in this program, focused only on plants and with minimal advertising or marketing, which resulted in fifteen hundred new registrants, a thousand new sites, and tens of thousands of observations on 133 plant species across the nation in less than a year.

Participants tended to stay involved, reporting most phenophases for an average of nine unique dates over almost two months during the year. This suggests sustained interest in participation and that the online interface and status monitoring engage the public, keeping them involved in the project and in participatory monitoring and outdoor activities.

The data collected by participants show interesting patterns of plant phenology on regional to national scales that are commensurate with our understanding of climatological gradients associated with latitude, longitude, elevation, and degree of continentality. As such, these data should be useful to a variety of stakeholders interested in the spatial and temporal patterns of plant activity on a national scale. Through time, these data should empower scientists, resource managers, and the public in making decisions concerning adaptation to variable and changing climates and environments.