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Rhododendron macrophyllum
Also called California Rhododendron, California Rose Bay, California Rosebay, Californian Rosebay, Coast Rhododendron, Western Rhododendron
Pacific rhododendron is a large-leaved evergreen shrub or small tree from the Pacific coast of North America and the state flower of Washington. It grows best in cool, moist, acidic woodland conditions with partial shade.
Rhododendron macrophyllum, also known as the Pacific rhododendron, California rose bay, California rhododendron, coast rhododendron or big leaf rhododendron, is a large-leaved species of Rhododendron native to the Pacific Coast of North America. It is the state flower of Washington.
Archibald Menzies found R. macrophyllum growing along with Arbutus menziesii in May 1792 when he and George Vancouver made their second landfall after leaving Hawaii, near present-day Port Discovery, Washington. 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.
The species contains andromedotoxin, which can poison the honey of nearby hives.
The northern limit of its range is somewhat north of the border between Canada and the United States in British Columbia. It is found as far south as Monterey Bay in California. It is widely distributed in the Coast Mountains and Cascade Range. It is less abundant in the coastal mountains of Washington and northern Oregon and more common south of the Siuslaw River. It is mostly coastal in distribution but extends its range eastward to locations in the Cascade Mountains in Oregon, Washington and British Columbia.
Rhododendron album · Rhododendron anthopogon · Rhododendron argyrophyllum · Rhododendron augustinii · Rhododendron bureavii · Rhododendron calophytum · Rhododendron calostrotum · Bell Flowered Rhododendron · Bent-style rhododendron · Rhodora · Catawba rosebay · Georgian Snow Rose
Text excerpted from the Wikipedia article Rhododendron macrophyllum by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
Pet safety from the ASPCA toxic and non-toxic plant lists.
