Native Plant Spotlight: Osoberry
I’m looking forward to leading a native plant exploration in Larrabee State Park in April! We’ll begin our day by framing ecosystem ecology in the Pacific Northwest through the lenses of forest ecology, plant community composition, local climate, and biogeochemical cycling. Once we have established a baseline of local ecological knowledge, we will dive into plant identification and community ecology.
We will discuss plant taxonomy, field identification techniques, and processes as we encounter new species. We will also build a deeper knowledge of each species by examining interactions between plant species, pollinators, and wildlife. Last but not least, we will look at plants through the lens of historical and contemporary human uses. Let’s have a look at one of my favorite locals: osoberry!
Osoberry (Oemleria cerasiformis) Ecology and Identification
A common shrub in Larrabee State Park and throughout the Fraser Depression is osoberry. Osoberry – also known commonly as Indian Plum – is often found in open Douglas-fir (Psuedotsuga menziesii) forest on river terraces growing in mesic alluvial soils.
Osoberry is a dioecious (male and female plants are separate) short-lived shrub with five white petals at home in the lowlands below 1000 meters. Osoberry is one of the earliest species to break dormancy, with bud and expansion and leaf and flower emergence occurring by late February. Early leaf out allows osoberry shrubs access to full sunlight before leaf emergence in overstory deciduous trees blocks direct light. Male plants flower first and produce 3 times the number of female plants. Osoberry does poorly in low-light conditions where fruit set becomes limited.
Osoberry-wildlife interactions
The early emerging flowers of osoberry provide native bees, moths, butterflies, and hummingbirds an early-season nectar resource when flowers are few. Later in the year, the fruits provide a resource for mammals such as American black bears (Ursus americanus) and bird species, including cedar waxwings (Bombycilla cedrorum) and American robins (Turdus migratorius). In turn, animals move the seeds to new locations, which helps to spread osoberry populations.
Osoberries and People
First Nations peoples have used osoberry as a minor food source, both fresh and cooked. The fresh leaves are also edible but quite bitter. The points of harpoons were affixed to the shaft using the outer bark of Osoberry. A note of caution: People should not ingest the crushed seeds of osoberry because they contain cyanoglucosides,
Osoberry is also a popular plant in restoration ecology due to its ease of cultivation, fast growth, and fibrous root system that binds riparian soils and helps to prevent stream-side erosion.
Text and photos by Chris Byrd, except top photo courtesy of Burke Herbarium Image Collection and illustration by Erin Savoy.
References
MacKinnon, A., & Pojar, J. (2016). Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia & Alaska. Lone Pine Publishing : Partners Publishing : B.C. Ministry of Forests.
Stein, W. (n.d.). Oemleria Cerasiformis . https://www.fs.usda.gov/nsl/Wpsm/Oemleria.pdf
USDA. (2016, April 4). Indian plum, Oemleria cerasiformis. Indian Plum Plant Fact Sheet. http://nativeplantspnw.com/indian-plum-oemleria-cerasiformis/