Canada has a rich history of observations in plant phenology, with data gathered by sources including volunteer networks, individual naturalists or biologists, and government projects in agriculture and forestry. This data is essential to an understanding of how plants will respond to future climates. It can also help in decision making for applications as diverse as the prediction of allergy onset, agricultural pest control, and in determining the future distribution of tree species.

Data on phenology in North America covers short periods (maximum 50 years) and is often discontinuous. In Canada, the oldest extensive database is that of the Royal Society of Canada, which gathered dates for 170 natural events from 1893 to 1922. Nova Scotia students provided a very large data set for this period, thanks to the efforts of education superintendent Dr. Alexander MacKay, also secretary of the Botanical Club of Canada. More recent surveys include the Alberta Wildflower Survey, which has tracked 3 bloom stages for 15 native plant species since 1987, with the help of about 200 volunteers annually. Plantwatch (www.devonian.ualberta.ca/pwatch) began in 1995 and has enlisted volunteers in North America and internationally to track spring bloom times of eight plant species useful as key indicators for phenology. Since 2001 this program has expanded with assistance from Environment Canada's Ecological Monitoring and Assessment Network Coordinating Office (EMANCO) and coordinators have been found for each of the provinces and territories. A booklet "Plantwatch: Canada in Bloom" was produced spring 2002 by the Canadian Nature Federation, describing the program and plant species. See www.plantwatch.ca to learn more about the program, report dates and see your observation instantly mapped. Spring is coming earlier in western Canada. Some trees and shrubs are developing one to four weeks earlier than a century ago. Eastern Canada shows less change. It is time to engage citizen scientists across North America in tracking the "green wave of spring"! Canada Plantwatch now has methods which match much of the European phenology networks. If we can develop a matching program in the USA, with observations of a suite of native and introduced plant species, we can then work with Europe to track phenology events on a very wide geographic basis.