Tag Archives: flowers

Magic Along the Oregon Coast – Rhododendron macrophyllum

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A bit of magic happens along the Oregon Coast in April and May—the wild rhododendrons begin to bloom! 

R. macrophyllum comes in a variety of colors from red to white. Photo by R. Prchal used with permission.

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.

Local display

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.

History

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.

Habitat

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.

Warfare

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.

From https://landscapeplants.oregonstate.edu/plants/rhododendron-macrophyllum

Beautiful and Fragrant Rhododendron occidentale

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The Pacific Coast area has only one native azalea which is famous not only for its fragrance and beauty, but also as being very difficult to grow.

Unlike our native rhododendron R. macrophyllum, R. occidentale is considered to be an azalea or azaleadendron. Both plants have a tendency to grow in thickets and become fairly tall. Unlike R. macrophyllum, R. occidentale is a deciduous azaleadendron and drops all of its leaves in the winter.

Colorful and fragrant blooms

The fantastic, often fragrant blooms, appear when the leaves emerge. Imagine 6-12 five multicolored florets clustered into trusses measuring up to 5-6 inches wide covering a large shrub.

These florets typically flaunt white, orange, yellow, pink or red, with flares, stripes, blotches, and frilly lobes that are deliciously fragrant.

Habitat

The flower and plant diversity reach a peak in the southern Oregon/northern California region spawning creating several unusual, recognized natural selections. This plant is also unusual because it will grow in serpentine soils (which are more base in pH). They are often used for southern coast restoration projects.

R. occidentale was used to develop fragrance and diversity in many other deciduous hybrid azaleas (such as Exbury hybrids). To see or smell a local example on campus check the southwest corner of Nash; southeast of Gilkey Hall at intersection of sidewalks in late April and May.

Where to look

Look for plants growing on the hillsides along Highway 101 from Newport to southern California. Fragrance will also give their locations away.

While it easily grows here, it will not on the East Coast. No one quite understands why it will not grow well there, especially since the bulk of native azealeas grow there.

Natural Cluster

It is possible to view a major natural cluster at the Azalea State Reserve just south of the Oregon-California border (see https://www.stateparks.com/azalea_state_reserve_in_california.html) near to Highway 101. There are several campgrounds, parks, reserves, etc. nearby.

Brookings, just north of this area in Oregon, features an annual Azalea festival. Check out occidentale at the Brookings City Park May 22-25, 2020. The festival includes many activities such as art shows, plant sales, seafood feeds, cruise ins, breweries, much and more! (see http://azaleafestivalbrookings.com/ )

For more information see OSU’s College of Agricultural Sciences, Department of Horticulture, Landscaping Plants at https://landscapeplants.oregonstate.edu/plants/rhododendron-occidentale and the Azalea Society of America at https://www.azaleas.org/view-azalea/?id=9318. Photo of R. occidentale by Don Hyatt, http://donaldhyatt.com/ used with permission.