This data package contains tulip phenology data consisting of 21,148 total observational reports from 1996 - 2020 across North America. These data were collected by 6,645 community scientists for Journey North, a crowdsourced participatory science program of the University of Wisconsin-Madison Arboretum. The Journey North Tulip Test Garden Project is an ongoing study of tulip phenology conducted at broad spatial and temporal scales. Since 1996, community scientists have tracked planting, emergence, and blooming of tulips (Tulipa L.) in the United States. Most observations should be of the Red Emperor Tulip, but not all observations can be validated as this species. Researchers are encouraged to read observer comments to confirm tulip species. Observers also provide estimates of the number of tulips sighted. However, observers do not follow standardized methods for counting species observed. Observers do not observe at set times of the day, do not repeat observations regularly, and are not required to provide the length of time during which a specified number of species observed were counted. Therefore, it is recommended that this dataset be analyzed to indicate broad phenological information. Researchers are encouraged to read the rich information provided by volunteers in their comments. These comments provide qualitative information about observational reports. Researchers are also encouraged to refer to submitted photographs that also provide context for observational reports. The Journey North Tulip Test Garden Project dataset is hosted by the University of Wisconsin-Madison Shared Web Hosting Service.