Sexing Osoberry (Oemleria cerasiformis) for Fruit Production for Birds

One of the earliest blooming native shrubs of the Pacific Northwest is Osoberry (Oemleria cerasiformis), making it is an important native shrub to include in habitat gardens as a nectar source for early emerging pollinators.  Osoberry is dioecious, which means it has male and female organs on separate plants.  In order for Osoberry to produce fruit (drupes) and seeds for birds, which they are highly attracted to, you must have one of each.

Once Osoberry is in bloom, which typically occurs in mid to late February, it's time to sex them.  In my case, I already had two males and was on the lookout for two females.  About six weeks ago, knowing Osoberry was in bloom, I visited a couple of native plant nurseries to look for females, which I was able to find, and now have Osoberry drupes already visible--they usually ripen by summer. 

Sexing male Osoberry: look for fifteen stamens and a five-petal calyx:

Sexing female Osoberry: look for five pistils and a five-petal calyx: 

I just love Osoberry!  From its purplish-brown bark to white, five-petal blossoms to bright, light-green, lance-shaped leaves to ovoid, bluish-black drupes, you'll feel right at home in the Pacific Northwest with this in your yard!  


Osoberry appreciates moist to dry soil and part-sun, often found growing along streambank terraces in the understory of open coniferous forests at low elevations.  Can get up to 15' tall and 5-10' wide.  Plant with companion plants such as Douglas fir, western red cedar, vine maple, Pacific ninebark, western bleeding heart, Cascade Oregon grape, sword/deer ferns, Oregon oxalis, and others.  The genus Oemleria contains a single species: Osoberry.  I've always thought that was pretty cool.