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

Rhododendron ''Rhododendron'' (; : ''rhododendra'') is a very large genus of about 1,024 species of woody plants in the Ericaceae, heath family (Ericaceae). They can be either evergreen or deciduous. Most species are native to eastern Asia and the Himalayan ...

'' native to the

Pacific Coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas North America Countries on the western side of North America have a Pacific coast as their western or south-western border. One of th ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It is the state flower of Washington.

Description

It is an

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

shrub A shrub or 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 trees by their multiple ...

growing up to tall. The

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

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

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

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

Distribution

The northern limit of its range is somewhat north of the border between

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. 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. San Francisco itself is further north along the coast, by about 75 miles (120 km), accessible via California S ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It is widely distributed in the

Coast Mountains The Coast Mountains () 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 British Columbia Coast, Coast of British Columbia sout ...

and

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

. 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 United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

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 o ...

. 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. During his naval expeditions, h ...

found ''R. macrophyllum'' growing along with '' Arbutus menziesii'' in May 1792 when he and

George Vancouver Captain (Royal Navy), Captain George Vancouver (; 22 June 1757 – 10 May 1798) was a Royal Navy officer and explorer best known for leading the Vancouver Expedition, which explored and charted North America's northwestern West Coast of the Uni ...

made their second landfall after leaving

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, near present-day

Port Discovery, Washington Port Discovery, Washington is the name of a historically significant community in Jefferson County, Washington that was located on Discovery Bay for roughly a hundred years; it disappeared in the late 20th century, with the collapse of the local t ...

.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. In recent years it has been the main focus of a study group at the Rhododendron Species Foundation in Federal Way, Washington, 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, 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 Flora of the Western United States Garden plants of North America Symbols of Washington (state) Flora without expected TNC conservation status