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US National Arboretum


Azalea Blossom Watch 2005

Current Conditions

April 1st | April 8th | April 15th | April 22nd | April 29th | May 6th | May 13th
May 20th | May 27th

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 Images of azalea blossoms 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 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 often as we update you on the current conditions in this years Azalea Blossom Watch. Check below for information and images in our "weekly" update of what you can see in the Azalea Collection. [Note: Some links below will show you a 'mouse-over' pop-up image. Try it here].


   April 1st image of Daffodil blooms

To the untrained eye, it might still seem like winter outside. At the US National Arboretum, however, the staff are busily mulching, pruning and planting. The first signs of spring are showing up all over our 446 acres. Daffodils, cherries and magnolias are in color with their pastel blooms. For the next eight weeks, Barbara Bullock, curator of Azaleas and Rhododendrons will attempt to describe the azaleas as spring unfolds in the Azalea Collections. Current projections for the peak season of bloom for the Azalea Collections is April 25, with a week of spectacular display on either side of that date.

  image of Rhododendron mucronulatum azalea blossoms

Today on this misty rainy day, the earliest of rhododendrons is in bloom. Rhododendron mucronulatum (the Manchurian Azalea) blooms before its new leaves emerge. Several cultivars and selections exist: 'Cornell Pink' named for its light clear pink blossoms; albiflorum - a white selection; and the most common lavender-flowered forms are seen dotting the garden paths of the Azalea Collections. Also in bloom are numerous plants of Pieris japonica (also known as Japanese Andromeda) raised from seed collected from its native Japan.


   April 8th image of Weston hybrid 'Peach Blend'

The azaleas in the National Arboretum Azalea Collections are slowly beginning to open up. With cooler than average temperatures but not freezing, the normally early-blooming species are in spectacular color. The Manchurian (also called Korean) Azaleas (Rhododendron mucronulatum) and the Weston hybrids, such as 'Peach Blend', are at their best bloom right now. Magnolias and cherries are also holding onto their blooms and can be seen through out the Arboretum grounds.

Weston's hybrid 'Peach Blend', a hybrid of Rhododenron keiskei (a pale yellow semi-evergreen from Japan) and R. mucronulatum 'Cornell Pink' (a pink selection of the Manchurian azalea from Korea) can be seen from the road as one drives past the eastern side of the Azalea Collections on Eagle Nest Road.

The Glenn Dale Azalea Hillside, which draws thousands of visitors in the spring, is due to reach peak bloom at its normal time around the 25th of April with a week of spectacular display on either side of that date. This week we noticed the first hint of color in the buds of one of the early pinks. The dogwoods are ready to pop and daffodils are blooming all over the grounds.


   April 15th image of Weston hybrid 'PJM Elite'

More and more azaleas are blooming in the National Arboretum's azalea collection. The Glenn Dale azaleas (over 10,000 plants) are showing at 5% open as of April 13, but should continue to show more color by the weekend. Our cherries and magnolias have never looked better. The dogwoods are beginning to open up and daffodils are blooming through out the grounds.

Early every spring, there are some azaleas & rhododendrons which always bloom first: The Weston azaleas are the most spectacular at this time. The cultivar 'PJM' is the most popular and widely available for sale in nurseries. We also have Rhododendron keiskei (a pale yellow semi-evergreen from Japan) and Rhododendron reticulatum (a pink deciduous azalea from Japan) in bloom.

If you plan to make your visit for the peak bloom, which we expect will be on schedule (between April 20 and May 8), then we recommend coming before 3pm Monday through Friday, or before 2pm during the weekends.


   April 22nd image of 'Portent' Glenn Dale Azalea

The temperatures are soaring into the high 80's at the National Arboretum this week. This causes early blooming plants like some of the magnolias, the cherries, and daffodils to quickly fade. On the other hand, it causes the blossoms of many of the Glenn Dale azaleas to open. Some Glenn Dales you'll see in bloom today include 'Allure', 'Dayspring', 'Festive', 'Geisha', 'Morning Star', 'Portent', 'Refrain', and 'Sebastian'.

Some of the later Weston Group selections are now in full bloom such as 'Landmark' and 'Olga'. These are the semi-evergreen small-leaved rhododendrons which give interest to the azalea landscape through out the year. The double-flowered Yodogawa Azalea, (Rhododendron yedoense) was named before its single-flowered cousin, (Rhododendron yedoensis var. poukhanense) the common Korean Azalea. The double-flowered form received the shorter name because it was described first by botanists in 1692.

This weekend should be spectacular for the Azalea Collection. Even if we get the predicted light rain showers, the garden will be perfect for strolling and taking photographs.


   April 29th image of Kureme hybrid azaleas

Spring is in full swing at the National Arboretum. We've had a remarkably cool March and April, but without the typcial late spring freezes that we sometimes get.

So, this has caused the overall bloom schedule of the azaleas to be set back about a week, which is fine, because the Kurume hybrid azaleas are in bloom now, and they are georgous!
Here's 'Pink Lady'. The Florida Flame azalea, (Rhododendron austrinum) is also in bloom.

This weekend, April 30 - May 1 will surely be the peak flowering of the Azalea Collection. As long as this wonderful weather continues, the following weekend (May 7th & 8th; Mother's Day) will be spectacular as well.


   May 6th image of Kurume hybrid group of azaleas

The azaleas are now at PEAK bloom and have been for over a week. If this cool weather keeps up, they will remain in peak bloom through Mother's Day weekend and the week following. The cool weather preserves the open blossoms. Because of this, the early-flowering Kurume hybrid group of azaleas are still in wondrous bloom.

Noted for their tiny flowers which cover the plant and dense branching habit, the many colors and forms of the Kurume azaleas can still be observed along the Henry Mitchell Cultivar Walk (view of Kurume azaleas; view of salmon azaleas; view of red azaleas). Here are a few other hillside views (here and here).

Other interesting azaleas are also coming into bloom. The beautiful orange of 'Aromi Sunrise' (a selection of a cross with the native Rhododendron austrinum) can be seen from a long distance away. And while the native coast azalea (Rhododendron atlanticum) is not so showy, its fragrance can turn a head from twenty feet away.


   May 13th image of Rhododendron austrinum 'Millie Mac' azalea flowers

The peak bloom of azaleas on Mt. Hamilton may have subsided, but the wooded collection has not dimmed. While some of the earlier azaleas to bloom have started to drop their flowers, hundreds of other cultivars are still opening.

Many of the Glenn Dale azaleas, bred by the National Arboretum's first director B. Y. Morrison, were specifically selected because of due to their later bloom times and larger flowers. See 'Kobold' and 'Bagatelle' lighting up the north entrance trail leading into the collection. 'Vespers' has large white flowers with a hint of yellow in each flower.

Other azaleas to make their entrance at this time are the Hirado hybrids such as 'Heiwa no Hikari' with its large orangy red flowers. The native coast azalea (Rhododendron austrinum) has a beautiful selection called 'Millie Mac' with unusual two-toned flowers and a fragrance to match. The later Kurume hybrids such as 'Orange Cup' begin to make their appearance at this time with bold reddish orange rounded flowers covering the shrub. Another deciduous azalea to show off its blossoms is the yellow 'Lemon Lights'. This azalea was selected in Minnesota with extreme hardiness in mind but does well in our climate as well. The old variety 'Narcissiflora' is a double form of a yellow deciduous azalea from the Ghent hybrid group. The very old evergreen variety called 'Magnifica' is often seen in older gardens around our area.

There are many more surprises in the Azalea Collections for weeks to come. Don't hesitate to schedule a visit and learn about the many varieties of azaleas that are available.


   May 20th image of Morrison Garden azalea flowers

The azaleas at the National Arboretum are still blooming strong. The Morrison Garden is at its peak right now. Some of the later varieties include the Glenn Dale introductions that are on display in and around the Morrison Garden; the Robin Hill hybrids are beginning to bloom such as 'Betty Ann Voss'. This is the time that the large leaf rhododendrons begin to bloom.

Did you know that the botanical name of all azaleas is Rhododendron? Take a look at their flower structure; their seed development and you'll understand why botanists have classified all azaleas in the genus Rhododendron.


   May 27th image of Glenn Dale 'Pink Star' azalea flowers

Most of the evergreen azaleas in the Arboretum's Azalea Collections are finished blooming for the year. The rains we had this and last week have exacerbated the petal blight problem. [More information about this fungal disease can be found on our IPM Tips page]. Symptoms include spotting and wilting of the flowers.

And yet, there are still many more azaleas ready to bloom: The Satsuki, Robin Hill- and some Glenn Dale hybrids have many late blooming azalea cultivars. One of the earliest of the Satsuki hybrids to bloom is 'Meicho'. It has beautiful large four inch blossoms which are multi-colored on the same plant. Many Robin Hill hybrids are coming into bloom this week. The double flowers of 'Scott Gartrell', 'Lady Louise', 'Laura Morland' and 'Maxine West' delight all who view them. Some late Glenn Dales which were selected for their late bloom times are the spotted 'Acrobat', the iridescent 'Nocturne' and the coral flowers of 'Pink Star'. Our Pink Star' is only 5 feet tall, but has a spread of over 25 feet wide.

Mountain-laurels have made their way into gardens with many new cultivars and this is their season. This week 'Nipmuck', 'Carousel', 'Little Linda', and the diminutive 'Elf' as well as the straight species, Kalmia latifolia, are all coming into bloom.

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Last Updated   May 27, 2005 1:25 PM