Northern Illinois Native Seed Phenology

Phenology is defined as: “The study of phenomena or happenings. It is applied to the recording and study of the dates of recurrent natural events (such as the flowering of a plant or the first or last appearance of a migrant bird) in relation to seasonal climatic changes. Phenology thus combines ecology with meteorology” (https://www.britannica.com/science/phenology). Based on this definition, native seed phenology includes the study and recording of dates associated with seed development for plants known to be native for a given region.

One aspect of native seed phenology is knowing when the seed of a specific native species is “ripe” or ready for harvest. Due to variation in plant genetics, location (in terms of latitude/longitude and microhabitat), and weather conditions, individual plants of a given species will not be ripe at the same time.   Understanding seed phenology and native seed collection date ranges is important, especially for habitat restorations and for supporting our declining native pollinator populations. Pollinators including hummingbirds, native bees, and other insects require nectar and pollen throughout the duration of the growing season. If restoration ecologists only collected and spread seeds from a particular species during an average prime seed ripening window instead of from plants whose seeds are ripe earlier or later than average, the amount of genetic material that will eventually be spread to other restoration areas is limited. If the genetic material is limited, then flowering dates/ranges of a plant species and therefore pollen and nectar sources may be limited as well. To encourage the spread of genetic diversity for a given plant species, it is highly recommended to consider collecting ripened seeds throughout the entire range of its seeding dates.

The goal of the following Northern Illinois Native Seed Phenophases document is to provide a free and accessible comprehensive resource for native seed collection planning and those involved with habitat restoration in northern Illinois. The seed collection date ranges utilized in this chart was kindly collected and donated by ecologists, restoration professionals, and trained volunteer scientists associated with the Lake County Forest Preserve District, the Forest Preserve District of DuPage County, the McHenry County Conservation District, the Nature Conservancy (Nachusa Grasslands), Citizens for Conservation, and the Forest Preserves of Cook County (The North Branch Restoration Project and Poplar Creek Prairie Stewards). Thank you to all who was involved with data collection/organization over the years and who provided comments and feedback to draft versions of this chart!