Azalea Blossom Watch

Current Conditions

May 26th, 2004 (Final)
The first days of summer are upon us with temperatures soaring in the high 80's. image of azalea blossoms

And yet, many cultivars of evergreen azaleas are still in bloom in the National Arboretum azalea collection. Noteably the Satsuki hybrids and the North Tisbury group. There are also some Robin Hill azaleas in bloom.

image of azalea blossoms
The Frederic P. Lee Azalea Garden, dedicated April 30, 1970 is the epicenter of our late blooming azalea collection. Focusing primarily on the Satsuki hybrid group of azaleas, the Lee Garden is in full bloom right now. Surrounding the Lee Garden are plantings of North Tisbury and Robin Hill azaleas. The North Tisbury azaleas make an excellent groundcover with their tendency to creep or grow into mounds.

image of azalea blossoms

Although this is the last installment of the Azalea Blossom Watch, there are still more azalea blossoms to come. One of our favorites is the native deciduous plumleaf azalea (Rhododendron prunifolium) which has brilliant red blossoms in June and July. Then later in the fall, the Encore azaleas bloom their second time.

May 20th
While the Periodical Cicadas are humming and the sweet fragrance of Japanese Honeysuckle surrounds us, some late blooming azaleas are still coming into bloom in the National Arboretum's Azalea Collection.

image of azalea blossoms

The Frederic P. Lee Azalea Garden, dedicated April 30, 1970, contains a collection of late blooming azaleas, primarily the Satsuki hybrid azaleas. This serene garden, located on the northeastern slopes of the collection, is surrounded by other late blooming varieties as well, such as the Robin Hill hybrids, and the North Tisbury hybrid azaleas. Follow the Henry Mitchell image of azalea blossoms Cultivar Walk, and you will locate varieties of azaleas which will extend the bloom season in any garden. They will always bloom 2-3 weeks after what we call "peak" bloom, and coincide with the blooming of the Mountain Laurel. Also blooming among the evergreen varieties listed above, are some selections of summer flowering deciduous azaleas known as Weston Group azaleas.

May 13th
The first flush of azaleas has passed in the National Arboretum's azalea collection, but that doesn't mean that the blooming season is over. There are hundreds of cultivars of mid to late season evergreen azaleas still coming out. The Glenn Dale cultivar 'Martha Hitchcock' is now on display. Each flower has a strong reddish-purple margin surrounding a white center. The flowers are each three inches across.

image of azalea blossoms
There are more surprises in store in the Frederic P. Lee Garden of the Azalea Collections. This serene garden has a quiet pond, benches and contains an extensive collection of Satsuki azalea cultivars. One of the earliest to bloom, 'Meicho', has multi-colored flowers over four inches in diameter on the same plant. This feature called "sporting" is often seen in the Satsuki azaleas. Most of the Satsuki azaleas bloom in late May and early June.

image of azalea blossoms

The Satsuki, meaning "fifth month" were developed over hundreds of years by the Japanese. Plant explorers in the 1930's onward were delighted with the wide range of varieties, and brought cuttings of these plants back from their travels. Some of the Satsuki cultvars were used in the development of the Glenn Dales.

May 6th
'Tis the time of the mid-season blooming azaleas! Most of our early Kurume hybrids and early Glenn Dales have finished their bloom cycle. The dogwoods are about fininshed, and there are just a few iris beginning to bloom here and there. There are literally hundreds of varieties of azaleas to be seen in bloom in the Collection. This is the reason that many of the Glenn Dale azaleas were bred, that is to extend the season of azalea bloom.

Discover such cultivars such as 'Chanticleer' and 'Dauntless', with their image of azalea blossoms deep purplish red, two inch blossoms. They glow. The cultivars 'Moonbeam' and 'Glacier' are two lovely whites, but 'Moonbeam's flowers are nearly four inches across. Some native North American species azaleas are in bloom, such as Rhododendron austrinum, R. alabamense, R. atlanticum, and several deciduous azalea cultivars, such as 'Sunny Side Up', an 'Aromi' hybrid.

image of azalea blossoms

The Morrison Garden, a prominant feature in the Azalea Collections, was dedicated 50 years ago, on May 3, 1954, as a tribute to Benjamin Y. Morrison and his extensive work on the Glenn Dale azaleas.

April 28th
The National Arboretum azaleas are at their peak, and will remain so for the next week or two. Heavy rains or extremely warm temperatures will cause the blooms to drop sooner, but let's not think about that. The Glenn Dale azaleas are at 50% bloom, while the early blooming Kurume hybrid azaleas are at 100%. Several native Rhododendron austrinum (the Florida Flame Azalea) are blooming with their orange blossoms and can be seen along the Henry Mitchell Cultivar Walk.

The Morrison Garden, dedicated May 3, 1954, is 50 years old this year, and displays the very best of the 454 Glenn Dale hybrid azaleas. Benjamin image of azalea blossoms Y. Morrison was Chief of Plant Exploration and Introduction at Glenn Dale, Maryland while he was also serving as acting director of the National Arboretum was the hybridizer of the Glenn Dale azaleas. He became the Arboretum's first director in April, 1951, shortly before he retired that November. The beautiful azalea hillside was planted with as-yet unselected Glenn Dales, approximately 15,000, in 1946-47. The Arboretum officially opened its grounds to the public in the spring of 1959.

Parking for the azalea collection is best at the M Street parking lot. A short walk will bring you to the Morrison Garden, into the center of the Azalea Collection.

April 21st
The azaleas are opening up at a rapid rate since we started getting image of azalea blossoms

warmer days in the 80's. The weekend of the FONA plant sale (April 23-24) should be perfect for wandering in the azalea gardens. Many early varieties of Kurume, and Glenn Dale hybrid azaleas are in bloom. (See photo to right).

The Japanese Torch azalea, Rhododendron kaempferi is on fire with orangy red blossoms. This species was used prominantly in breeding hardiness and height into many of the Glenn Dale Azaleas. The native North American species, Rhododendron austrinum, (the Florida Flame Azalea) is showing off it's bright orange blossoms today as well. I hope to see you in the garden!

April 14th
Thousands of azalea blossoms are puffed and ready to burst into bloom here at the National Arboretum. The weather pattern has been sustaining 40 degrees-plus temperatures day and night for several days now, which keeps the buds in a holding pattern. As of today, April 14, the blossoms remain at a less than 5% opened. The good news is we haven't had one of our famous late frosts. Keep your fingers crossed.

If we get the warm weather predicted for Sunday, 4/18, the azaleas will begin opening in earnest. The collection may be closed one day next week for up to 6 hours, so that we may spray a fungicide to control the disease "azalea petal blight", a condition whereby the flower fails to develop due to a fungal disease called Ovulinia. So far, the predicted peak bloom is for the weekend of April 24 - 25.

Because of no late frosts, and the cool weather, the Arboretum is aglow with the blossoms of our cherries, magnolias and many varieties of daffodils. There are some early flowering azaleas to be seen in the Azalea Collections, such as Rhododendron reticulatum, a lovely lavender Japanese species also known as the Rose Azalea. A pale yellow flowering species called Rhododendron keiskei is also in bloom today, with its semi-evergreen leaves, it is sometimes called a "small-leaved rhododendron".

April 7th
The Azaleas are now at 5% open mostly on the southern side of the collection facing Azalea Road. There is even one in bloom in the Morrison Garden, which is 50 years old this year. this Glenn Dale azalea, 'Geisha' is usually one of the first Glenn Dales to bloom.

There are numerous other Rhododendron cultivars in bloom now such as the 'PJM', 'Llenroc', and 'Pink 'n' Sweet'. These can be seen along the Henry Mitchell Cultivar Walk.

April 1st
The Azaleas are beginning to open on the southern most side of the collection above the Azalea Road parking lot. This is unusually early for the evergreen Glenn Dale azaleas. We are seeing some open flowers and lots of bud color. The cool weather isn't hurting a bit, due to the fact that night time temperatures are maintaining above freezing.

The early flowering Manchurian Azalea, (Rhododendron mucronulatum) is also blooming this week, and can be seen near the Morrison Garden and along the Henry Mitchell Cultivar Walk. Daffodils and other spring flowering bulbs are planted throughout the garden are in bloom as well.

At this time, we expect the peak azalea bloom to be around the third week of April, and the weekend of April 24th to be spectacular.

Experience the National Arboretum's treasured
Azalea Collections. Experience the explosion of color when thousands of azaleas at the National Arboretum light up the forest with their subtle shades and colors. The best time to come see the azaleas is during the last two weeks of April and the first week of May. 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. The best time to schedule your visit is on a week day, 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 can also be frustrating as other visitors slow down to take a moment. If you can afford the time and take a walk, it is worthwhile to park in the nearby M Street parking area, and walk to the Morrison Garden. Pick up a brochure there, and begin your journey into the world of azaleas.

You can also visit our Azalea Photo Gallery were you will find over 200 images of the flowers of more than 100 of the Glenn Dale azalea varieties.

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Last Updated April 1, 2005 12:03 PM
URL = http://www.usna.usda.gov/Gardens/collections/azaleablossom.html

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