Azaleas // are flowering shrubs in the genus Rhododendron, particularly the former sections Tsutsuji (evergreen) and Pentanthera (deciduous). Azaleas bloom in spring, their flowers often lasting several weeks. Shade tolerant, they prefer living near or under trees. They are part of the family Ericaceae.
Plant enthusiasts have selectively bred azaleas for hundreds of years. This human selection has produced over 10,000 different cultivars which are propagated by cuttings.[ citation needed] Azalea seeds can also be collected and germinated.
Azaleas are native to several continents including Asia, Europe and North America. They are planted abundantly as ornamentals in the southeastern US, southern Asia, and parts of southwest Europe.
According to azalea historian Fred Galle, in the United States, Azalea indica (in this case, the group of plants called Southern indicas) was first introduced to the outdoor landscape in the 1830s at the rice plantation Magnolia-on-the-Ashley in Charleston, South Carolina. From Philadelphia, where they were grown only in greenhouses, John Grimke Drayton (Magnolia's owner) imported the plants for use in his estate garden. With encouragement from Charles Sprague Sargent from Harvard's Arnold Arboretum, Magnolia Gardens was opened to the public in 1871, following the American Civil War. Magnolia is one of the oldest public gardens in America. Since the late 19th century, in late March and early April, thousands visit to see the azaleas bloom in their full glory.[ citation needed]
Azalea leafy gall can be particularly destructive to azalea leaves during the early spring. Hand picking infected leaves is the recommended method of control.[ citation needed]
In Chinese culture, the azalea is known as "thinking of home bush" (sixiang shu), and is immortalized in the poetry of Du Fu.
Azaleas and rhododendrons were once so infamous for their toxicity that to receive a bouquet of their flowers in a black vase was a well-known death threat. 
In addition to being renowned for its beauty, the azalea is also highly toxic—it contains andromedotoxins in both its leaves and nectar, including honey from the nectar.  Bees are deliberately fed on Azalea/ Rhododendron nectar in some parts of Turkey, producing a mind-altering, potentially medicinal, and occasionally lethal honey known as " mad honey".  According to the ancient Roman historian Pliny the Elder in his Natural History,  an army invading Pontus in Turkey was poisoned with such honey, resulting in their defeat. 
Motoyama, Kōchi also has a flower festival in which the blooming of Tsutsuji is celebrated and Tatebayashi, Gunma is famous for its Azalea Hill Park, Tsutsuji-ga-oka. Nezu Shrine in Bunkyo, Tokyo, holds a Tsutsuji Matsuri from early April until early May. Higashi Village has hosted an azalea festival each year since 1976. The village's 50,000 azalea plants draw an estimated 60,000 to 80,000 visitors each year.
Sobaeksan, one of the 12 well-known Sobaek Mountains, lying on the border between Chungbuk Province and Gyeongbuk has a royal azalea ( Rhododendron schlippenbachii) festival held on May every year. Sobaeksan has an azalea colony dotted around Biro mountaintop, Gukmang and Yonwha early in May. When royal azaleas have turned pink in the end of May, it looks like Sobaeksan wears a pink Jeogori (Korean traditional jacket). 
The Ma On Shan Azalea Festival is held in Ma On Shan, where six native species ( Rhododendron championae, Rhododendron farrerae, Rhododendron hongkongense, Rhododendron moulmainense, Rhododendron simiarum and Rhododendron simsii ) are found in the area. The festival has been held since 2004; it includes activities such as exhibitions, photo contests and carnivals. 
Many cities in the United States have festivals in the spring celebrating the blooms of the azalea, including Summerville, South Carolina; Hamilton, NJ; Mobile, Alabama; Jasper, Texas; Tyler, Texas; Norfolk, Virginia;  Wilmington, North Carolina ( North Carolina Azalea Festival);  Valdosta, Georgia;  Palatka, Florida ( Florida Azalea Festival);  Pickens, South Carolina;  Muskogee, Oklahoma; Brookings, Oregon; and Nixa, Missouri.
The Azalea Trail is a designated path, planted with azaleas in private gardens, through Mobile, Alabama.  The Azalea Trail Run is an annual road running event held there in late March. Mobile, Alabama is also home to the Azalea Trail Maids, fifty women chosen to serve as ambassadors of the city while wearing antebellum dresses, who originally participated in a three-day festival, but now operate throughout the year.[ citation needed]
The Azalea Society of America designated Houston, Texas, an "azalea city".[ citation needed] The River Oaks Garden Club has conducted the Houston Azalea Trail every spring since 1935.[ citation needed]
- "Home & Garden Information Center - Clemson Cooperative Extension - Clemson University, South Carolina". www.clemson.edu. Retrieved 22 June 2018.
- Benson, D.M. "Azalea Diseases in the Landscape". Plant pathology extension NCSU. North Carolina State University. Retrieved 27 January 2011.
- Municipal law of the city of São Paulo nr. 14472 of 2007.
- "Stopping to Smell the Rhododendron | Natural Selections". selections.rockefeller.edu. Retrieved 2016-11-02.
- "University of Pennsylvania's Poisonous Plants Home Page". Archived from the original on 2012-03-17.
- "The Strange History of 'Mad Honey' - Modern Farmer". modernfarmer.com. 4 September 2014. Retrieved 22 June 2018.
- Pliny. Natural History. p. 24.90.
- Pliny. Natural History. p. 21.77.
- Department of Culture & Tourism, Danyang-gun County Office
- "Native Azaleas in Hong Kong" (PDF).
- "Ma On Shan Azalea".
- Norfolk NATO Azalea Festival Website
- "North Carolina Azalea Festival - A Scene to be Seen!". North Carolina Azalea Festival. Retrieved 22 June 2018.
- Valdosta, Georgia, Spring Celebration at Callaway Gardens in Pine Mountain, GA, Azalea Festival Website
- "FLAZALEAFEST.COM". www.flazaleafest.com. Retrieved 22 June 2018.
- "Pickens Azalea Festival". www.pickensazaleafestival.org. Retrieved 22 June 2018.
- "City of Mobile, Azalea Trail Maps".
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