Using Smoke-Water and Cold-Moist Stratification to Improve Germination of Native Prairie Species

Published in Native Plants Journal: As the capability of land management agencies to restore degraded habitat at large scales has improved, the availability of native plant materials has become a primary limiting factor in the restoration process. Developing clear protocols for a suite of regionally important restoration species will increase the feasibility and cost effectiveness of native species production on a commercial scale. A full factorial design was used to test a 1:100 smoke-water imbibe treatment coupled with 6 lengths of cold-moist stratification (0, 15, 30, 60, 90, and 120 d) to determine if 10 selected South Puget Sound prairie species have a dormancy that is broken by some combination of these factors. Plant-derived smoke-water is a proven germination cue in other fire-adapted ecosystems; however, smoke-water had a significant influence for only one—Aquilegia formosa Fisch. ex DC. (western columbine; Ranunculaceae)— of the 10 tested species after the 90-d stratification period. The duration of cold-moist stratification time had a significant effect on 8 of the analyzed species. Of those 8 species, 7 reached a maximum germination rate before the standard protocol guideline of 84-d cold-moist stratification, suggesting that stratification for species with unknown germination requirements may need to be shortened. Stratification times identified here will provide guidance and will improve production efficiency for producers interested in propagating these prairie species for restoration.