Rhododendron macrophyllum, the Pacific Rhododendron, Coast Rhododendron or Big Leaf Rhododendron, is a broadleaf evergreen

Evergreen

In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 rhododendron

Rhododendron

Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...

species native to western North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

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Distribution

Pacific rhododendron is found along the Pacific Coast from British Columbia to Monterey County in California [30,41]. It is widely distributed in the Coast and Cascade Mountain Ranges [9,30,43]. Pacific rhododendron is less abundant in the Coastal Mountains of Washington and northern Oregon and more common south of the Siuslaw River

Siuslaw River

The Siuslaw River is a river, approximately 110 mi long, along the Pacific coast of Oregon in the United States. It drains an area of approximately in the Central Oregon Coast Range southwest of the Willamette Valley and north of the watershed of the Umpqua River.It rises in the mountains...

 [27].

The northern limit of the range of the Pacific Rhododendron is somewhat north of the border between Canada and the US in British Columbia. It is found as far south as Monterey Bay

Monterey Bay

Monterey Bay is a bay of the Pacific Ocean, along the central coast of California. The bay is south of San Francisco and San Jose, between the cities of Santa Cruz and Monterey....

 in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It is mostly coastal in distribution but extends its range eastward to locations in the Cascade Mountains in Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

, Washington and British Columbia

British Columbia

British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

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Description

It is a shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 growing 2–9 m tall. The leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

, retained for 2–3 years, are 7–23 cm long and 3–7 cm broad. The flower

Flower

A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

s are 2.8–4 cm long, with five lobes on the corolla; color is usually pink, although variants exist.

Habitat

This species, like many rhododendrons, thrives in disturbed habitats such as roadside embankments and recently deforested wildlands. The photo at the top of this page was taken in a forest in Oregon that was burnt over just three years before the time of the photo (2005). The rhododendrons in that area, both Pacific Rhododendrons and Western Azaleas, are already regrowing and blooming from the unburnt roots.

History and cultivation

Archibald Menzies

Archibald Menzies

Archibald Menzies was a Scottish surgeon, botanist and naturalist.- Life and career :Menzies was born at Easter Stix in the parish of Weem, in Perthshire. While working with his elder brother William at the Royal Botanic Gardens, he drew the attention of Dr John Hope, professor of botany at...

 found this shrub growing along with Arbutus menziesii in May of 1792 when he and George Vancouver

George Vancouver

Captain George Vancouver RN was an English officer of the British Royal Navy, best known for his 1791-95 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of contemporary Alaska, British Columbia, Washington and Oregon...

 made their second landfall after leaving Hawaii, near present day Port Discovery

Port Discovery, Washington

Port Discovery, Washington is the historical name of what is now called Discovery Bay, a bay in the U.S. state of Washington on the south side of the Strait of Juan de Fuca, on Washington's Olympic Peninsula. It was also called Port Discovery Bay for some time, a name that can be found on maps from...

. Seed was sent to England in 1850 by William Lobb

William Lobb

William Lobb was a Cornish plant collector, employed by Veitch Nurseries of Exeter, who was responsible for the commercial introduction to England of Araucaria araucana from Chile and the massive Sequoiadendron giganteum from North America.He and his brother, Thomas Lobb, were the first...

.

Pacific Rhododendron shrubs can be scraggly and the flowers are often much less impressive than those of its relatives. Also, it is easy to kill this plant with an excess of summer watering - while not watering it can leave it looking pathetic. In its native range and once established it can be a trouble free attractive plant requiring a minimum of attention.

In recent years it has been the main focus of a study group at the Rhododendron Species Foundation

Rhododendron Species Foundation and Botanical Garden

The Rhododendron Species Foundation and Botanical Garden is a nonprofit botanical garden specializing in rhododendrons, located at 2525 South 336th Street, Federal Way, Washington...

 in Federal Way, Washington, the Western North American Rhododendron Species Project (WNARSP). The WNARSP is documenting the detailed range and forms of all of the western North American rhododendron species.

Symbolism

The Pacific Rhododendron is the state flower of the state of Washington in the USA.

Other sources

• Davidian, H. H. The Rhododendron Species, Volume III - Elepidotes continued. 1992. Timber Press. ISBN 978-0-88192-168-7.
• Cox, Peter A. & Kenneth N.E. The Encyclopedia of Rhododendron Species. 1997. Glendoick Publishing. ISBN 978-0-9530533-0-8.