Influence of seed stratification and seed age on emergence of Penstemon

Abstract

Studies were conducted to evaluate the effect of stratification and seed age on percent seedling emergence of Penstemon. Emergence differences occurred between the eight Penstemon selections, as well as between seed stratification treatments and seed age. Seed stratification significantly increased emergence. Emergence varied from 0% with 1-year-old seed of Penstemon digitalis with no stratification, to 72.8% emergence with 2-year-old seed of P. angustifolius with 10 weeks of stratification. Seedlings from 3- to 4-year-old seed generally emerged as well as or better than with 1- and 2-year-old seed. Percent emergence varied significantly with stratification, seed age, and species. Some emergence occurred with species from seed up to 10 years old.