What are Rhododendrons?

Tricia Christensen
Tricia Christensen

Rhododendrons are shrubs which include many varieties. They occur as native plants in Southeast Asia, North America, and in tropical climates from India to Australia. It is related to blueberry and heather plants. Rhododendrons are often confused with azaleas. In fact the two plants are of the same species. Azaleas, however, tend to be a great deal smaller, and present with more color variations than do the large bushy rhododendrons.

Rhododendrons are prone to aphid infestations, but ladybugs can help.
Rhododendrons are prone to aphid infestations, but ladybugs can help.

Most rhododendrons can grow to be massive bushes, taller than 6-8 feet (1.82-2.43m). Established gardens of rhododendrons can grow even taller. One of the most interesting of these gardens is the Rhododendron Dell in Golden Gate Park in San Francisco. Here one finds tall bushes that have been thriving for over thirty years. The Dell is exceptionally beautiful in May when the rhododendrons burst in fantastic blooms of white, pink, orange and purple.

White rhododendrons have a sweet aroma akin to root beer.
White rhododendrons have a sweet aroma akin to root beer.

The funnel shaped blossoms of rhododendrons cluster together to form the appearance of single large flowers. Rhododendrons are also praised for the scent of their blossoms, which is a heavy sweet smell. White rhododendrons seem to often have the heaviest scent, which has an aroma akin to root beer. The bushes themselves have shiny, oblong, dark green leaves, which are evergreen. Most rhododendrons are in fact, evergreens, however, azaleas have both evergreen and deciduous varieties.

Rhododendrons thrive with little care, often growing wild. They are somewhat aggressive, and some cultivars from North America have become persistent to the point of annoyance in parts of the UK. The plants are notoriously hardy once firmly established. If one is considering planting rhododendrons, partial to full shade and acidic soil seems to help the plant thrive.

Garden rhododendrons may be vulnerable to some pests, including aphids. Since aphid infestations are short-lived, they usually do not pose much problem to the plant. Each area where the plant is grown, and each variety will have varying degrees of susceptibility to a few plant diseases such as root rot and petal blight. Most suburban areas have Rhododendron Societies that can help you decide which plants are best suited for your area and are most resistant to diseases.

The American Rhododendron Society offers information on their website which can also help one in selecting the best plants for one’s area. They also choose a Rhododendron of the Year for each of the geographical locations. In 2006 for example, the Point Defiance rhododendron has earned the title, and is considered an excellent choice for gardeners in the Northwestern portion of the US. Growers in the northeast states are invited to try the frost resistant Ken Janeck rhododendron.

If you are new to growing rhododendrons, the Society can be of tremendous help with selection and information about types, varieties and growing information. If you are just an admirer of flowers, the site is still worth a visit. The photography and information is excellent.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


Early May and azalea bushes are blooming all over Cambridge, MA near Harvard, and the scent is amazing - a bit spicy, cinnamon-y, a bit like carnations.


I spent a great deal of time in the rhododendron Dell in SF growing up. I can attest to a root beer scent to the white blossoms. However, there are many varieties, so perhaps there are unscented whites, too. Best to you.


The white and slightly pink hued blossoms on my rhododendron (about 40 years old) have a beautiful subtle scent and do not smell like root beer! My deep red and magenta colored rhodies have no scent, and no one I know has heard of a scented rhodie.

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