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US National Arboretum


Azalea Blossom Watch 2015
Current Conditions

April 3 | April 20

Experience the National Arboretum's treasured Azalea Collections

Spring is upon us once again, and the National Arboretum is rich with bloom from the spring ephemerals to the daffodils, magnolias and cherries planted throughout the grounds. This column which begins today and will change each week for the next eight weeks will focus specifically on our Azalea Collections and the status of bloom.

Experience the explosion of color when thousands of azaleas at the National Arboretum light up the forest with their subtle shades and colors.However, the first azaleas begin to bloom in early April with the daffodils and the forsythia, and still others are blooming as late as July with the daylilies. We hope that this Azalea Blossom Watch will give you insight into the range and diversity of the Rhododendron species and cultivars growing at the National Arboretum, as well as help you with planning your visit.

Images of azalea blossoms

The best time to schedule your visit is on a weekday, but if weekends are your only option, a stroll through the garden before noon or during a light rain offers an enviable second choice. A drive around Azalea Road can be exhilarating because of the views of the collection, but if you can afford the time to take a walk, it is worthwhile. Pick up a brochure at one of the three major entrances to the collections or at the Visitor Information center and begin your journey into the world of azaleas.

Learn more about the Azalea Collection here. For more in-depth information on growing and caring for rhododendrons or azaleas, check out the FAQ pages here. Visit our Azalea Photo Gallery where you will find over 200 images of the flowers of more than 100 of the Glenn Dale azalea varieties.

In the meantime, check back here each week as we update you on the current conditions in this year's Azalea Blossom Watch.

April 3

Greetings to our friends and guests!
Today we begin our weekly azalea blossom watch updates. For the next eight weeks, Azalea Collections Curator Barbara Bullock will describe the azaleas as the season unfolds.

Peak Bloom Prediction
Spring is taking the slow approach this year. With temperatures hovering on the cool side, (daytime averages in the mid-fifties throughout the month of March), the azaleas are not quite ready to show their colors. As long as temperatures remain cool, we predict peak bloom to be around the end of April or early May. 

Current Conditions
Very few early Rhododendron species are beginning to show color in the Azalea Collection.,  This week R. mucronulatum (lavender), swollen buds of R. keiskei (pale yellow) and R. reticulatum (pinkish-lavender) are ready to open any day.  This spring, cherries, magnolias, and daffodils are blooming later than usual due to the cool temperatures. 

Bald Eagle Nest On Glenn Dale Hillside
We are excited to report that a family of bald eagles have built a nest in a tall poplar tree situated among the Glenn Dale azaleas.  To learn more about the eagles,  you can visit our website: We have temporarily closed a portion of the Azalea Collection (about 30%) to preserve and protect them while they raise their young.  When visiting the collection, you will not be able to drive around Azalea Road until early summer, but you can easily view most of the garden if you walk from one of the Arboretum parking lots.

April 20

azaleaThis week, the Azalea Collection has many buds showing a hint of color forecasting the brilliant display to come in the next few weeks. Last week, temperatures soared to the low 80’s. This is quite warm for the early flowering plants like daffodils and many of the cherries and magnolias, speeding up their blooming period. The warm temperatures will also speed up the opening of early azaleas.  

Early species such as Rhododendron mucronulatum, and the Weston hybrids are in bloom today. They consistently flower at the same time that forsythia in is full bloom.  The evergreen azaleas that are showing color this week include many of the Glenn Dales which are planted in and around the Morrison Azalea Garden, and the reliable but beautiful Kurume azaleas found along the Henry Mitchell Cultivar Walk.  A few of our native deciduous species such as Rhododendron austrinum (the Florida Flame Azalea) will be in bloom by the end of the week. 

For information on when and how to prune azaleas, when the best time to plant and transplant azaleas and much more, check out our FAQ link at:

See you in the garden.


Click here for images of the collection.

You can also read the Azalea Blossom Watch from
2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, and 2004.

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Last Updated   April 24, 2015 2:36 PM

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