''Rhododendron macrophyllum'', the Pacific rhododendron, California rosebay, California rhododendron, coast rhododendron or big leaf rhododendron, is a large-leaved species of ''

Rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

'' native to the

Pacific Coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

. It is the state flower of

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

Description

It is an

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

growing up to tall. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

, retained for 2–3 years, are long and broad. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s are long, with five lobes on the

corolla Corolla may refer to: *Corolla (botany), the petals of a flower, considered as a unit *Toyota Corolla, an automobile model name *Corolla (headgear) A ''corolla'' is an ancient headdress in the form of a small circlet or crown.Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...

. It is found as far south as

Monterey Bay Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. It is widely distributed in the

Coast Mountains The Coast Mountains (french: La chaîne Côtière) are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbi ...

and

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

. It is less abundant in the coastal mountains of Washington and northern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and more common south of the

Siuslaw River The Siuslaw River ( ) is a river, about long, that flows to the Pacific Ocean coast of Oregon in the United States. It drains an area of about in the Central Oregon Coast Range southwest of the Willamette Valley and north of the watershed of th ...

. It is mostly coastal in distribution but extends its range eastward to locations in the Cascade Mountains in Oregon, Washington and British Columbia.

Habitat

''Rhododendron macrophyllum'', like many rhododendrons, thrives in disturbed habitats such as roadside embankments and recently deforested wildlands. They can also live up in the mountains. It also grows in coastal and montane conifer woods.

History and cultivation

Archibald Menzies Archibald Menzies ( ; 15 March 1754 – 15 February 1842) was a Scottish surgeon, botanist and naturalist. He spent many years at sea, serving with the Royal Navy, private merchants, and the Vancouver Expedition. He was the first recorded Euro ...

found ''R. macrophyllum'' growing along with ''

Arbutus menziesii ''Arbutus menziesii'' or Pacific madrone (commonly madrone or madrona in the United States and arbutus in Canada), is a species of broadleaf evergreen tree in the family Ericaceae, native to the western coastal areas of North America, from Br ...

'' in May 1792 when he and

George Vancouver Captain George Vancouver (22 June 1757 – 10 May 1798) was a British Royal Navy officer best known for his 1791–1795 expedition, which explored and charted North America's northwestern Pacific Coast regions, including the coasts of what are ...

made their second landfall after leaving

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, near present-day Port Discovery, Washington.Justice, Clive L. Mr. Menzies' Garden Legacy, Plant Collecting on the Northwest Coast. 2000. Cavendish Books. Seed was sent to England in 1850 by

William Lobb William is a male given name of Germanic origin.Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford University Press, 2nd edition, , p. 276. It became very popular in the English language after the Norman conquest of Engl ...

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

Federal Way Federal Way is a city in King County, Washington, United States. One of the most recently incorporated cities in the county, its population was 101,030 at the 2020 census. Federal Way is the tenth-largest city in Washington and the fifth-larg ...

, the Western North American Rhododendron Species Project. The WNARSP is documenting the detailed range and forms of all of the western North American rhododendron species.

Toxicity

The species contains

andromedotoxin Grayanotoxins are a group of closely related neurotoxins named after '' Leucothoe grayana'', a plant native to Japan originally named for 19th century American botanist Asa Gray. Grayanotoxin I (grayanotaxane-3,5,6,10,14,16-hexol 14-acetate) is als ...

, which can poison the honey of nearby hives.

References

Other sources

*Davidian, H. H. ''The Rhododendron Species, Volume III – Elepidotes continued''. 1992. Timber Press. . *Cox, Peter A. & Kenneth N.E. ''The Encyclopedia of Rhododendron Species''. 1997. Glendoick Publishing. .

External links

* * {{Taxonbar, from=Q2714739

macrophyllum The long-legged bat (''Macrophyllum macrophyllum'') is a member of the Phyllostomidae family in the order Chiroptera. Both males and females of this species are generally small, with wingspans reaching 80mm with an average weight ranging betwee ...

Flora of the Western United States Garden plants of North America Symbols of Washington (state) Flora without expected TNC conservation status