A bit of magic happens along the Oregon Coast in April and May—the wild rhododendrons begin to bloom!
Rhododendron macrophyllum or more commonly the ‘Western Rhododendron’ produces a lovely five-lobed, bell-shaped bloom. Imagine 20 or more single pale pink to rosy-purple blooms clustered in trusses that cover a small tree or large shrub with large green leaves. Now imagine miles of blooms peeking out on each side of road.
Blooms are visible along State Highway 101 typically during late April and early May. Some communities, such as Florence, Oregon, even host an annual festival (May 14-16, 2021) with parades, flower shows, and many family-friendly activities. Festivals and displays, such as these plant festivals, can be a fun and easy expeditions for garden buffs.
R. macrophyllum, discovered in 1792, thrives along the Pacific coastline from British Columbia, Canada through northern California. R. macrophyllum was selected as Washington’s State Flower in 1892 (see https://www.worldatlas.com/articles/what-is-the-state-flower-of-washington-washington-state-flower.html ) and is currently being studied by the Rhododendron Species Foundation, in Federal Way, Washington, and local American Rhododendron Society Chapters.
R. macrophyllum thrives in disturbed habitats such as roadside embankments and recently deforested wildlands. They can also live in mountainous areas.
If you hear disparaging comments about rhododendrons from Loggers or Foresters it is probably about this plant. Unlike most other rhododendrons, R. macrophyllum (and other plants in the Pontica section) create a very thick undergrowth which can make some terrains nearly impossible to traverse.
A few rhododendrons in the Pontica section, like R. macrophyllum, contain a natural neurotoxin (grayanotoxins). Persians and Greeks used this knowledge in warfare, literally using rhododendron honey to over-throw invading armies.
No part or product (such as honey) made from R. macrophyllum should be consumed or used by humans. Do not burn the wood in a campfire–see Texas A&M University at https://research.tamu.edu/2014/11/03/how-eating-mad-honey-cost-pompey-the-great-1000-soldiers/ and Scottish Centre for Infection & Environmental Health (https://www.bmj.com/rapid-response/2011/10/28/honey-poisoning-beware-rhododendron. Bees are not affected.
For more information see: OSU’s College of Agricultural Sciences, Department of Horticulture, Landscaping Plants at https://landscapeplants.oregonstate.edu/plants/rhododendron-macrophyllum and the American Rhododendron Society at https://www.rhododendron.org/descriptionS_new.asp?ID=114.