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US National Arboretum


Azalea Blossom Watch 2012
Current Conditions

April 5 | April 13 | April 26 | May 3 | May 10 | May 17 | May 24 | May 31

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. In 2012, the peak azalea bloom should be around April 15. 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 5

The area's warm temperatures in February and March have caused the azalea bloom to follow directly on the heels of the cherries this year. On March 28th, the Glenn Dale azalea Hillside was 10% open - two weeks ahead of the average start of flowering. With this trend, we can expect the peak bloom for the azaleas at the National Arboretum to be around April 15th. We have recorded early peak bloom dates before: In 1999 it was April 15th, and in 1998, April 18th. It can also be very late; peak bloom was May 4th in 1996. If April's highs this year remain in the 70s, the succession of azalea bloom will last well into May.

April 13

Everyone keeps asking if there will be any azaleas left at the end of April. The answer is yes, and they will be as beautiful as ever.

The mid-season azaleas are just now starting to show bud color and will be joining the early azaleas in splendid harmony this weekend. The early azaleas have lasted longer than usual due to the steady cool temperatures we’ve been getting for the past 3 weeks. Many deciduous azaleas are in bloom this week as well. With colors like yellow and orange, they contrast wonderfully with the crimson and violet evergreen azaleas. It is unusual to see so much azalea color when the oak trees have just begun to sprout their leaves.

See you in the garden!

April 26

Cool weather and heavy rains have not diminished the mid-season azaleas that are opening now in the Azalea Collections. We are still experiencing the effects of the early spring this year, and the azaleas blooming now are about three weeks ahead of their usual time. The Glenn Dale azalea hillside one sees by driving around Azalea Road is about 75% finished blooming for the year due to its early start and its southern exposure. But many surprises await the visitor who ventures into the eastern portion of the collection on foot. This area, now in peak bloom, features an extensive selection of azalea cultivars, identified through interpretive signage and labels in the Morrison Garden, the Henry Mitchell Cultivar Walk, and the Lee Azalea Garden.

The Arboretum’s over 4,000 azalea hybrids all derive from species of Asian origin. These are the types commonly seen in the nursery trade and throughout gardens in the metropolitan area. They are arranged in the collection by color or hybrid groups and include the following: Glenn Dales, Belgian Indians, Pericats, Beltsville Dwarfs, early Robin Hills, Back Acres, and kiusianum selections. Most are evergreen.

There are at least three native azaleas in bloom now in this same area of the collections. The white-flowered coast azalea, Rhododendron atlanticum is extremely fragrant and native from Deleware to Georgia. The flame azalea, R. calendulaceum, is brilliant yellowish orange and native to the southern Appalachians, particularly the Smoky Mountains. The Florida flame azalea, R. austrinum, though native to a southern state, does perfectly well in our area. It is orange to yellow, fragrant, and can grow to 8 feet tall. All native North American azaleas are deciduous.

Click here for other images of the collection.

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

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Last Updated   April 26, 2012 6:14 PM

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