First-flowering dates of plants in the Northern Great Plains

Phenological observations of plant flowering patterns are a useful tool for studying the ecological impact of global climate change over long term periods. However, the long-term datasets with which meaningful comparisons can be made are rare, especially in the less-populated Northern Great Plains region of North America. Here we present the observations of first flowering time of native and non-native plant species in North Dakota and Minnesota over the course of 51 years in the last century. O.A. Stevens recorded the first-flowering time of 753 species in the vicinity of Fargo, North Dakota and throughout North Dakota from 1910 to 1961. These data offer baseline indications of both the timing of first flowering and the presence/absence for a wide variety of plants in a region of North America with a relatively short growing season.