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US National Arboretum


Azalea Blossom Watch 2017
Current Conditions

April 7 | April 20 | May 5

azaleaExperience the National Arboretum's treasured Azalea Collections

Spring is upon us once again, and the National Arboretum is rich with blooms – 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. The first azaleas begin to bloom in early April with the daffodils and the forsythia, while 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.

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. 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 bi-weekly as we update you on the current conditions in this year's Azalea Blossom Watch. Experience the National Arboretum's treasured Azalea Collections.

April 7

Greetings to our friends and guests! Each spring, thousands of azaleas bloom at the U.S. National Arboretum. This week we begin our bi-weekly azalea blossom watch updates from the curator, Barbara Bullock, on the status of the bloom season in the Azalea Collection.

Rhododendron reticulatumConditions of azaleas for spring 2017:
The azalea buds have successfully weathered the fluctuations of this season's spring. Like the cherries on the Tidal Basin, our Yoshino's are in peak bloom. Every year some plants are tricked into an early bloom by fluctuating temperatures in late February which affected some of the early cherries and magnolias as well as some of the early blooming Rhododendron hybrids, but there was no damage to the garden azaleas. Based on current conditions, I expect the crescendo of blooms to begin around April 15th with peak season landing sometime in the 3rd week of April.

Currently in bloom in the garden:
A lovely deciduous azalea from Japan, Rhododendron reticulatum, can be seen in full bloom in the Lee Azalea Garden. (I’ve seen it bloom as late as April 19th).  Spring bulbs such as daffodils, grape hyacinths, and early species tulips are adorning our trails in anticipation.  The Kurume and Glenn Dale azaleas are showing 5% color, and more flowers opening daily.

Bald Eagle Nest on Glenn Dale Hillside
We are excited to report that the family of bald eagles have returned to their nest built in a tall poplar tree situated among the Glenn Dale azaleas.  To learn more about the eagles, please 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 can easily view most of the azalea gardens if you walk from one of the Arboretum parking lots.  New this year: we have placed a viewing station telescope for the public’s use, to enjoy the eagles from afar.


April 20

R. Southern Indian ‘George Lindley Taber’This week, the Azalea Collection is in PEAK bloom.  The native flowering dogwoods (Cornus florida) are blooming as well. With the warm temperatures in February, the azaleas are at least one week to 10 days ahead of their usual bloom time. The early blooming of the azaleas combined with the blooming dogwoods makes a gorgeous combination in the garden. The weekend’s forecast for some much needed rain should be perfect for photographs.  For a short walk to the azaleas, parking in M Street lot is recommended at this time of year.

Red Azaleas at north entrance to the azalea collection.  ‘Ben Morrison’ below right. The evergreen azaleas that are flowering 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.  We are even seeing the beginning of the bloom for the mid-season azaleas such as ‘Ben Morrison’ and ‘George Lindley Tabor’.

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:


May 5

Rhododendron fortuneiIt’s time for the mid-season bloomers.  While the peak bloom of azaleas has passed, there are many still in bloom today and many more to come. One of the primary objectives of first USNA Director B. Y. Morrison’s azalea breeding program was to extend the season of bloom for azaleas.  Known collectively as the Glenn Dale azaleas, these can be seen growing in and around the Morrison Garden and are planted throughout the Azalea Loop within their color groups. 

Other azaleas types in bloom are the Robin Hill, North Tisbury and Satsuki hybrid groups.  Each group is planted together in collections along the Henry Mitchell Cultivar Walk.  The Robin Hill azaleas have larger flowers and are generally less than five feet tall.  The North Tisbury’s have lustrous dark foliage with brilliant pink, red, or orange flowers.  All of the North Tisbury’s are fairly low growing and spreading.  They are selections of the Japanese species Rhododendron nakaharai.  One of the selections ‘Nakami’ grows only one inch tall.  The Satsuki, meaning "fifth month" were developed over hundreds of years by the Japanese. The Satsukis bloom during the months of May and early June. 

The larger leaf Rhododendrons are also coming into bloom.  Requiring ideal drainage and a lot of space, they are creating a spectacular show this week throughout the Azalea Collection as well as in Fern Valley, the Dogwood Collection and the Asian Collections.  See you in the garden!

Click here for images of the collection.

You can also read the Azalea Blossom Watch from
2016, 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, and 2004.

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Last Updated   May 5, 2017 10:25 AM

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