Rhododendrons in the Redwoods
The Redwood Zone
Redwoods once covered much of Western North America. Now the Coast Redwood biome is restricted to a band near the Pacific Ocean shoreline from just south of San Francisco to just north of the Oregon border, stretching inland no more than fifty miles. Sequoia sempervirens specimens can live in excess of a thousand years and are the tallest trees in the world. Their height is possible only because of the benign coastal climate with mild winters and cool, often foggy, summers. They reach their greatest size in the area surrounding the Eureka Chapter of the American Rhododendron Society.
Two native species of Rhododendron grow in our area. The California or Western Rhododendron, Rhododendron macrophyllum (once called Rhododendron californicum), grows abundantly among the giant redwood trees and can be seen blooming in springtime along our highways. Stagecoach Hill north of Humboldt Bay is a world famous site for the Western Azalea, Rhododendron occidentale. Collectors and growers come from all over the world to view the azaleas and collect seeds at Stagecoach Hill.
This section of the redwood biome, the far north coast of California, is Rhododendron Central. That’s what the previous Executive Secretary of the American Rhododendron Society, Dee Daneri, called this area. She lived in Fortuna so may have been prejudiced, but it’s true. The moderating influence of the Pacific Ocean, producing those cool summers and mild winters, is most pronounced here. It allows us to grow rhododendrons that are from high altitudes in the Himalaya as well as tender ones from lower elevations that are often fragrant and the tropical Vireya Rhododendrons from the jungles of Southeast Asia. South of the San Francisco Bay Area it is difficult to grow hardy rhododendrons and north of the California state line it is difficult to grow tender rhododendrons. This area had one of the first commercial rhododendron nurseries on the West Coast. As early as 1915, Charles Ward of Cottage Gardens in Eureka was shipping 100,000 rhododendrons and azaleas by rail all over the United States, including to Oregon and Washington. Ward apparently understood the importance of this area for rhododendron propagation. The early rhododendron hybrids grew as well for him as the newer ones do for us today in the heart of the redwood biome.