Establishment of native seed is often impeded by competitive invasive annual grasses like Bromus tectorum and Ventenata dubia. To effectively use small quantities of high-value native seeds we need to understand their germination characteristics. Our goal is to develop methods to improve germination and seedling establishment. We examined species locally grown in western Montana that have a demonstrated or potential ability to compete for early season niche space with invasive annuals. We determined germination timing, potential dormancy, and seed structure of all species. In order to find out if we can manipulate these characteristics to improve their competitive ability, we ran a seed priming experiment. Seed priming has the potential to increase the germination percent, rate, and synchronicity. We tested a 60-day cold stratification or a 24-hour soak in deionized water, gibberellic acid (GA3), potassium nitrate (KNO3) or a worm cast slurry, with a focus on colder germination temperatures meant to mimic early season germination.
Results/Conclusions
We found species with characteristics that, left alone or manipulated with priming, could be beneficial in our efforts to revegetate and diversify harsh south-facing slopes and sites invaded by invasive annual grasses. Including a number of species that are known to need cold stratification to germinate that had a similar germination percentage with gibberellic acid priming (annuals: Collinsia parviflora, Phacelia linearis, Plantago patagonica, Polemonium micranthum; biennials/perennials: Grindelia squarrosa, Mentzelia laevicaulis, Penstemon albertinus). This allows us to have more flexibility with our seeding timing by fall seeding unprimed seeds or spring seeding primed seeds. There were additional species that required no priming or only responded to known pretreatment requirements (i.e. Eriophyllum lanatum requires cold stratification). These results will help us better plan restoration seeding efforts and take advantage of our locally adapted seeds. We are incorporating knowledge gained from this and other studies into our strategy for restoring south-facing slopes.