Rhododendrons are grown in many North American and European gardens; however, the rhododendron species originated from the East, brought to Europe by plant explorers.
The rhododendron species belong to the Ericaceae plant family; rhododendrons are botanically related to azaleas, blueberries, heathers and mountain laurels. The name rhododendron is derived from the Greek word rhodos (meaning rose) and dendron (meaning tree). There are over 1000,natural species of rhododendron; however, many rhododendron species found growing in North America and Europe today are hybrids.
Botanical Description of the Rhododendron Species
The Rhododendron Species is a diverse plant; rhododendrons grow as trees (some over 100 feet high), as bushes and as low ground cover. The leaf of a rhododendron is just as diverse as the plant itself; rhododendron leaves can grow over three feet long or be less than a quarter of an inch. Rhododendron leaves grow in a variety of shapes too.
The color of the rhododendron flower is available in nearly every color of the rainbow including various shades of blue, yellow, pink white, red, orange and purple. Rhododendrons flower from January through August, depending on the location and the climate.
Native Habit of Rhododendrons
The rhododendron species is native to Asia, particularly in the Himalaya mountains, northern India and western China; the rhododendron species was one of the plant specimens, together with the sweet box plant species, collected by Joseph Hooker, a director at Kew Gardens, on one of the many plant exploration trips to the East. Today, there are many rhododendron hybrids which are native to North America and Europe, as a result of cross pollination of many rhododendron species.
Suitable Climates for Rhododendrons
Rhododendrons grow in a wide range of climates; native rhododendrons are found in both arctic and tropical places in the world. Rhododendrons usually require adequate rain fall and moderate temperatures to flourish most successfully. Depending on the hybrid rhododendron species, rhododendrons grow well in the following areas in North America and Europe:
British Columbia (Canada)
San Francisco area
west coast of the United Kingdom
Azalea or Rhododendron?
Azaleas actually belong to the Rhododendron genus and the botanical name for azaleas includes Rhododendron in the species name. Azaleas may be evergreen or deciduous; evergreen species are native to southeast and central-east Asia whereas deciduous azaleas are native to Japan, China, parts of Eastern Europe and east and west Canada and the United States.
Many of the smaller rhododendron species resemble evergreen azaleas; however, most rhododendron flowers have 10 stamens and wider leaves whereas most azalea flowers have 5 or 6 stamens and narrow, pointy leaves. As always, there are may be exceptions to this rule, so it is always best to check when identifying the difference between a rhododendron and an azalea.
Species of Rhododendrons
Rhododendrons are a diverse and interesting plant species with beautiful flowers; the rhododendron species grows in various climates. An example of rhododendron species include:
Rhododendron maddenii – large, fragrant flowers; native to Nepal, Thailand and southeastern China
Rhododendron ciliatum – large, funnel flowers; native to Nepal, Tibet and Bhutan
Rhododendron triflorum – small, funnel flowers in various shades of yellow: native to the Himalayas, northern India and south east Tibet
Rhododendron edgeworthii – fragrant, white/pink flowers; native to the Himalayas.