Dormancy protects bottlebrush squirreltail seeds from germinating during seasonal dry periods.
Bottlebrush squirreltail seeds may germinate without a period of afterippening, showing a partial state of dormancy. However mean germination time for recently harvested seeds is longer than for afterippened seeds. Environmental conditions and timing of phenological events greatly affect the probability of recently harvested bottlebrush squirreltail seed germination. In central Washington, bottlebrush squirreltail prefers disturbed sites. In California, bottlebrush squirreltail is found in scattered stands at high elevations on dry, gravelly soils.