Azalea - Deciduous Species

All Azaleas fall into the Rhododendron family!
Azalea bushes thrive under the partial, filtered shade of pine, hickory and Oak, along with companion dogwood trees and camellia shrubs. Azalea plants prefer grown in partial shade, and when planted next to buildings, the north side offers protection from cold damage. The flowers of the azalea plant last longer in filtered pine tree shade because of the cooling effect. Pine tree straw, pine cones, and pine tree bark make excellent mulch under azaleas because it both cools and acidifies the soil. When planting azalea bushes, the shrub should be put into a landscaped hole containing 1/2 soil & 1/2 organic matter, such as peat moss, leaf gro or pine bark. Azalea plants are very shallow rooted and do not do well in compacted or heavy clay soils.
Azaleas love acidic soils, and a pH of 4.5 to 5.5 is perfect for vigorous growth. Watering may be essential if significant rainfall does not occur over two week period and fertilizing is usually not recommended. Fertilizer can burn the tender fibrous roots and may even kill the plant. If yellowing occurs in the leaves or leaf veins, Iron or Magnesium (Epsom salts) can correct the situation. NEVER put lime on an Azalea plant, not only is it wasting money, it can kill the plant.
Healthy Azaleas have bright green glossy leaves in the summer. If the leaves are dull green above and reddening below, that may signal phosphorous deficiency. It is ok to put a water soluble phosphorous fertilizer on the plant but AVOID NITROGEN!
Pruning should be done immediately after blooming to ensure good bloom the following season.
Azalea shrubs are propagated easily by taking a cutting about 8 inches long and placing the cut end about 2 inches deep in sand. These cuttings may root within a week during June and July, and the plant may grow another foot tall before being ready to be planted permanently. The seed requires light and should be surface sown and kept moist until germinating...pretreatment is not required.

* historical archive photo

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photo taken on Nov 19 2016 @ London Town Gardens, Edgewater, MD

Azalea alabamense ( Alabama Azalea )
A medium-size, rounded shrub reaching around 6 x 4 feet in 10 years and an eventual maximum size of 17 x 8 ( rarely over 11 ) feet, that is native to the Deep South, U.S.A. ( from central Tennessee to central Georgia; south to eastern Mississippi to central Alabama to northwest Florida )
The obovate leaves are up to 3.5 x 1.2 ( rarely over 2.5 ) inches in size. The foliage is semi-glossy, deep green above, light blue-gray beneath.
The fragrant flowers are white with a yellow blotch. They are borne in clusters of 6 to 10 during late spring.
Hardy zone 6 to 8 ( tolerating as low as -15 F ), thriving under tall limbed up pines.

* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.

* photos taken on Apr 21 2019 in Columbia, MD

var Colemannii ( Red Hills Azaleas )
Also called Azalea colemannii. It is native from central Alabama to central Georgia. It is very similar to Azalea alabamense but forms a non-rhizomatous, small tree, reaching a maximum height of 23 feet.

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photos taken on Aug 24 2017 @ U.S. Botanic Garden, Wash. DC.

Azalea albiflorum ( Cascade Azalea )
A fast growing, erect, upright deciduous shrub, native to coniferous mountain forests from southwest Canada into the northwest U.S. ( from Terrace, British Columbia to north-central British Columbia to Grande Cache, Alberta to Banff National Park, Alberta to western Montana; south to Oregon to Western Colorado ). It is endangered in Colorado and also extinct in Wyoming where its original range is uncertain. Some records include: 10 years - 4 feet; largest on record - 10 feet. It is rhizomatous and often forms colonies in the wild.
The oblong leaves, up to 4 x 1.2 inches in size, are finely-hairy. The foliage turns to intense orange-red during autumn.
The small, white, broad, bell-shaped flowers, up to 1.5 inches in length, are borne in trusses during late spring.
Hardy zones 4 to 6 ( western Montana and Alberta populations likely hardy in 3 ) and easy to grow.

* photo taken by Jean Pawek @ CalPhotos

* historical archive photos

Azalea albrechtii
A medium-size deciduous shrub reaching a maximum size of 13 x 8 feet ( rarely over 10 feet ) that is native to northern Japan. Some records include: 6 years - 6 feet.
The leaves, up to 5 x 2.5 inches, are deep green, turning to yellow in autumn.
The intense rosy-purple ( with olive-green spotting ) flowers, up to 1.6 inches wide, are borne in small trusses during mid-spring.
Hardy zones 5 to 8,( tolerating -20 F ). Prefers a woodland environment. It is easily grown from seed.

'Windsor Form'
Very good deep purple flowering form

Azalea arborescens ( Smooth Azalea )
A fairly fast growing, rounded, deciduous large shrub ( rarely a small tree ), native to mountain forests of the Appalachian Mountains of the eastern U.S. ( from eastern Kentucky to central and eastern Pennsylvania, south to central Alabama to central Georgia to central North Carolina ). Some records include: 10 years - 6 x 5 feet; largest on record - 27 x 27 feet.
The obovate to elliptical leaves are up to 4 x 1.5 inches in size. The foliage is glossy deep green, turning to red during autumn.
The very fragrant, white to light-pink, funnel-shaped flowers, up to 2.5 inches in length, are borne during mid spring either with or shortly after the foliage emerges.
The stems are smooth.
Hardy zones 4 to 8 ( tolerating as low as -30 F ) in partial to full shade on moist, acidic, well drained soil.

* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.

* photo taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

* photo taken on Apr 24 2016 @ U.S. National Arboretum, DC

* historic archive photo

'White Lightning'
A hybrid between Azalea arborescens & A. viscosum. Reaches up to 5 x 5 feet in 10 years, possibly wider with age. The very fragrant, large flowers, up to 2.5 x 2 inches, are bright white with a yellow center, borne early to mid summer.
The attractive foliage is blue-green.
Hardy north to zone 4

Azalea atlanticum ( Coast Azalea )
A stoloniferous, deciduous shrub, native to open sandy woods on the east coast of the U.S.A. from York Co. Pennsylvania & New Jersey, south to southern Georgia. In Maryland it is native to the eastern shore only. Some records include: 10 years - 6.5 x 6.5 feet; largest on record - 8 x 10 feet ( rarely over 6.5 feet ). This Azalea frequently spreads by stolons. On less than ideal sites, it rarely reaches over 3 feet in height, even at maturity.
The obovate leaves are up to 2.3 x 1.2 inches in size. The foliage is bright blue-green, turning to yellow during autumn.
The very fragrant, white, funnel-shaped flowers, up to 1.5 inches across, are borne in trusses of 4 to 10 during mid spring either just before or with the emerging foliage. The flowers are sometimes flushed with pink.
Hardy zones 4 to 8 in full sun to partial shade.

* photo taken on April 18 2010 @ U.S. National Arboretum, D.C.

* photo taken on May 6 2010 @ Brookside Gardens, Wheaton, MD

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photo taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photo taken on Nov 10 2020 @ Brookside Gardens, Wheaton, MD

* photo taken on Sep 10 2023 @ Smithsonian Institute, Wash., DC

* photos taken on May 6 2024 @ Brookside Gardens, Wheaton, MD

* photo taken on July 10 2024 @ Brookside Gardens, Wheaton, MD

'Biltmore Tall Form'
More vigorous, reaching up to 8 feet in height. It originated at the Biltmore Estate in North Carolina.
The attractive foliage is blue-green.
The fragrant flowers are white with a purple tinge.

'Marydel'
Vigorous and larger growing, to 10 x 10 feet, with lush bluish-green foliage.
The fragrant, large, intense pink flowers are rose-red in bud.

* photo taken on May 7 2014 @ London Town Gardens, Edgewater, MD

'Seaboard'
White flowers with a corolla tube that is pink.

Azalea austrinum ( Florida Azalea )
A rare, deciduous shrub, native to the southeastern U.S. ( from southeast Mississippi to central Alabama to central Georgia; south to northern Florida ). It is endangered in the wild and extinct over most of its original range in Georgia. Its native range is quite odd, it may actually grow more vigorously further north. Some records include: fastest recorded growth rate - 1 foot; 10 years - 6 x 4+ feet; 20 years - 14 x 8 feet; largest on record - 16 x 11.2 feet.
The obovate leaves, up to 5 x 2 inches in size, are downy at first, turning to deep green. The leaves turn orange and bronze-purple during autumn.
The abundant, very fragrant, orange ( less often golden-yellow or red ), funnel-shaped flowers, up to 1.5 inches in length, are borne trusses of 18 to 30 during late spring with the emerging foliage. The stamens are very long compared to most Azaleas.
Hardy zones 6 to 9 tolerating as low as -15 F. Very drought tolerant.

* photo taken on April 18 2010 @ U.S. National Arboretum, D.C.






* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.



* photos taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photos taken on Apr 24 2016 @ U.S. National Arboretum, DC

* photos taken on Apr 23 2017 @ Brookside Gardens, Wheaton, MD

* photo taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photo taken on Aug 24 2017 @ U.S. Botanic Garden, Wash. DC.

'Millie Mac'
A vase-shaped shrub reaching up to 6 x 4 feet in 10 years, eventually to 10 x 8 feet.
The flowers are fragrant, vivid yellow with a broad white wavy margin. The flowers are red-orange in bud. The foliage is mid-green.

'My Mary'
Spectacular, very fragrant, mid yellow flowers in mid spring. Reaches up to 6 x 5 feet in 10 years, eventually more.
Hardy zones 5 to 9

'Wise Decision'
A hybrid with Azalea calendulaceum. Abundant, extremely fragrant, golden-yellow flowers. Reaches up to 6 x 4 feet in 10 years, eventually more.

'Yellow River'

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

Azalea bakeri ( Cumberland Azalea )
Also called Azalea cumberlandense. A deciduous shrub, native from central Kentucky to southwest Virginia; south to eastern Alabama to northern Georgia to western South Carolina, mostly at above 3000 feet elevation. It is endangered in Virginia, North Carolina, South Carolina, Georgia and Alabama. Some records include: 10 years - 6 ( 8 ) x 4 feet; largest on record - 18 feet. It is found in deciduous forests and on mountaintops in the wild.
The obovate leaves are up to 3.2 x 1.5 inches in size. The foliage is deep blue-green above, waxy beneath.
The intense orange to orange-red, funnel-shaped flowers, up to 1.7 inches across, are borne in trusses of 4 to 7 during early to mid summer.
Hardy zones 5b to 9 tolerating as low as -25 F

* photos taken on May 17 2015 in Sandy Spring/Olney, Maryland

Azalea calendulaceum ( Flame Azalea )
An attractive, moderate growing, dense, large deciduous shrub, native to dry woods in the eastern U.S. ( from southern Ohio to southern New York; south to central Alabama to central Georgia ). It is most likely threatened with extinction in Ohio, Pennsylvania, New York State and Alabama. Some records include: 10 years - 8 x 8 feet; largest on record - 17 x 17 feet. This long-lived shrub, living up to 75 years or more, is a parent of many hybrid Azaleas.
The elliptic leaves are up to 5 x 1.5 inches in size. The foliage is downy mid-green, turning brilliant orange and red during autumn.
The abundant, lightly-fragrant, glowing orange ( less often yellow or red ), funnel-shaped flowers, up to 2.5 inches across, are borne in trusses of up to 7 during late spring, usually before the foliage.
Hardy zones 4 to 7 in full sun to partial shade.

* photo taken by Daniel O. Todd @ USDA-NRCS PLANTS Database

* photo taken on May 1 2010 @ U.S. Mational Arboretum, Washington, DC

* photos taken on May 7 2014 @ London Town Gardens, Edgewater, MD

* photos taken on Apr 28 2017 in Ellicott City, MD

* photo taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photos taken on Oct 18 2019 in Ellicott City, MD

* photos taken on Oct 24 2020 in Ellicott City, MD

'Dawn at the River'
Vigorous growing, reaching up to 6 x 4 feet. The very profuse, highly frarant flowers borne in dense clusters are glowing orange, yellow and red with all colors appearing on the same plant. Hardy zone 5 to 9

Azalea canadense ( Rhodora )
A compact, slender, medium-size, deciduous shrub, native to moist woodlands and bogs of northeastern North America ( from southeast Ontario to Quebec to Labrador, south to western New York State to northeast Pennsylvania to northern New Jersey ). It is endangered in Ontario, New York State and New Jersey. It is critically endangered in Ontario where it is only currently known from Alfred Bog east of Ottawa. Some records include: 10 years - 4 x 4 feet; largest on record - 8 x 4 feet.
The oblong leaves, up to 2.5 x 0.7 inches, are dull deep blue-green above, hairy beneath. The foliage turns greenish-yellow during autumn.
The 5-lobed, rosey-purple ( rarely white ), broad bell-shaped flowers, up to 1.5 inches across, are borne in small trusses during mid to late spring before the foliage emerges. The flowers are very frost tolerant.
The twisted branches are grayish in color.
Hardy zones 1 to 6, requires a cool humid climate and moist to wet, cool, acidic soil to thrive. It does not enjoy hot summers.

* USDA-NRCS PLANTS Database

* historical archive photos

'Album'
White flowers and bright green foliage.

Azalea canescens ( Piedmont Azalea )
A deciduous shrub, a widespread native of the southeastern U.S. ( eastern Oklahoma to southern Illinois to Kentucky to central North Carolina; south to eastern Texas to northern Florida ). Piedmont Azalea is also native to eastern Pennsylvania. It is endangered in Oklahoma, Illinois and Kentucky. Some records include: fastest recorded growth rate - 3 feet; 10 years - 10 x 10 feet; largest on record - 20 x 19 feet with a trunk diameter of 5 inches.
The obovate leaves, up to 3.5 x 1.5 inches in size, are deep green. Fall color isn't usually very spectacular but can be red. Piedmont Azalea looks great with blue flowering groundcover trailing beneath it.
The very fragrant, pinkish-white, funnel-shaped flowers, up to 1.5 x 2 inches, are borne in trusses of up to 14 during late spring.
Hardy zones 5 to 9 ( tolerating as low as -15 F ) in full sun ( if moist ) or partial shade. Drought tolerant.

* photo taken by Robert H. Mohlenbrock @ USDA SCS. 1991. Southern wetland flora

* photos taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photo taken on Aug 24 2017 @ U.S. Botanic Garden, Wash. DC.

* historic archive photo

'Camilla's Blush'
Very vigorous and fast growing, reaching up to 5 x 5 feet in 10 years, eventually to 8 feet.
The foliage is lush deep green.
The very fragrant, light pink ( with darker tubes ) flowers are borne on large clusters.

'Varnadoes Phlox Pink'
The fragrant flowers are intense pink, borne in very dense trusses.
Vigorous and upright growing, reaching up to 6 x 4 feet in 10 years, eventually reaching up to 8 x 8 feet.

Azalea dilatatum ( Mitsuba Azalea )
A deciduous, large shrub or small tree, reaching a maximum size of 17 x 25 ( rarely over 10 ) feet, that is native to southern Honshu Island in central Japan. It is endangered in the wild.
The smooth-edged, ovate to rounded leaves, up to 2 inches long, are clustered near the stem tips.
The intense lavender-purple flowers appear during mid-spring before the foliage emerges.
The smooth bark is reddish-brown.
Hardy zones 7 to 8 ( estimate..may prove hardier with further testing ).

* excellent photo link
http://www5e.biglobe.ne.jp/~lycoris/2009.04.19-1.7.JPG

Azalea flammeum ( Oconee Azalea )
A medium-size, dense, rounded deciduous shrub, native to the southeastern U.S. ( from northern & central Georgia to South Carolina ). It is endangered in South Carolina though was formerly widespread. Some records include: 10 years - 6 x 6 feet; largest on record - 12 x 10 feet.
The obovate leaves, up to 3.5 x 1.5 inches in size, are mid-green, often turning to orange during autumn.
The non-fragrant, orange, funnel-shaped flowers, up to 1.8 inches across, are borne in trusses of up to 12 during late spring.
Hardy zones 5 to 8 in partial shade on well drained soil. Very heat and somewhat drought tolerant.

* photos taken on May 1 2010 @ U.S. National Arboretum, D.C.


* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

Azalea japonicum
Previously known as Azalea mollis. A vigorous, dense, medium-size, deciduous shrub, that is a widespread native to mountains of southeastern China and Japan. Some records include: 10 years - 8 x 6 feet; largest on record - 17 x 7 feet.
The smooth-edged, oblanceolate leaves are up to 5 x 1.5 inches in size. The foliage is deep green above, bright green beneath; turning to red during autumn.
The abundant, intense orange ( less often yellow or scarlet-red ) funnel-shaped flowers, up to 4 x 4 inches, are borne in trusses of 10 to 12 during mid spring before the foliage emerges.
The smooth bark is grayish-brown.
Hardy zones 5 to 8 tolerating as low as -25 F. Thrives in sun or partial shade and is easy to grow.

* historic archive photo

Azalea kaempferi ( Kaempfer Azalea )
A dense, erect, deciduous to semi-evergreen large shrub, that is a widespread native to much of Japan. Some records include: 10 years - 17 x 10 feet ( usually half that ); largest on record - 17 x 19 feet with a trunk diameter of 7.4 inches.
The ovate to elliptical leaves are up to 3 x 1 inches in size. The mid-green foliage turns red-purple during autumn and persists well into winter. May be semi-evergreen in mild climates.
The spectacular, abundant, salmon-orange to brick red, funnel-shaped flowers, up to 2 inches across, are borne in trusses of 2 to 4 during late spring.
The smooth bark is blackish-brown.
Hardy zones 4 to 8 tolerating as low as -30 F. Sun loving, wind tolerant and very easy to grow.

* photos taken on April 11 2010 in Columbia, MD




* historic archive photo

'Albiflorum'
White flowers.

'Daimio'
Orangish-pink flowers.

'Dorset'

* photos taken on March 28 2010 @ U.S. National Arboretum, D.C.




'Mikawana'

* photo taken on April 18 2010 @ U.S. National Arboretum, DC


Azalea kiyosumese
Also called mayebarae. A dense, domed, medium-sized, deciduous shrub that is native to Kyushu Island of Japan. It can reach up to 5 x 4 feet in 10 years, eventually to 10 x 13 feet.
The leaves are up to 1.6 inches in length. The foliage turns an excellent fall color.
The intense light purple or red-purple flowers are borne during mid-spring.
Hardy zones 5 to 7 in full sun to partial shade.

Azalea luteum ( Pontic Azalea )
A vigorous, open, suckering, medium-size, deciduous shrub, native to eastern Europe into western Asia where it is commonly grown. It is naturalized locally in the British Isles. Some records include: 10 years - 4 feet; largest on record - 13 x 13 feet.
The oblong leaves are up to 6 x 1.5 inches in size. The foliage is deep green, turning intense orange, red and purple during autumn.
The strongly sweet-scented, large, intense yellow, tubular funnel-shaped flowers, up to 1.5 inches across, are borne in rounded trusses of 7 to 25 during mid-spring before the foliage emerges.
Hardy zones 3 to 6, it does not enjoy hot summers but where suited is easy to grow. It is also easy to propagate from hardwood cuttings taken during winter as well as from seed ,in fact it often self seeds.

* photo taken on April 18 2010 @ U.S. National Arboretum, D.C.

Azalea molle
A medium-size deciduous shrub, native to eastern China and much of Japan. Some records include: 10 years - feet; largest on record - 18 feet.
The oblong leaves, up to 6 x 2.3 ( rarely over 4 ) inches, are mid-green.
The large, golden-yellow to orange, funnel-shaped flowers, up to 3.5 inches in width, are borne in trusses of 6 to 12 during early spring.
Hardy zones 6 to 9. It is a parent of many hybrid Azaleas including the Mollis and Exburys.

Azalea nipponicum ( Nippon Azalea )
A deciduous medium-size shrub, reaching a maximum height of 7 feet, that is native to mountains of northern Honshu Island of Japan. Some records include: 10 years - 4 feet. It is endangered in the wild.
The large ( for an Azalea ) obovate leaves are up to 7 x 4 inches in size. The foliage is mid-green, turning intense scarlet-red during autumn.
The white tubular, pendulous flowers, up to 1 inches in length, are borne in trusses of 6 to 15 during mid-spring before or with the emerging foliage.
The very attractive bark peels away to reveal fresh red-brown bark beneath.
Hardy zones 6 to 8.

Azalea oblongifolium ( Texas Azalea )
A deciduous, small shrub, reaching a maximum height of 5 feet, that is native to pine-oak forests in the south-central U.S. ( from eastern Oklahoma to central Arkansas; south to northeast Texas to northern Louisiana ). It is considered by some to be a western subspecies of A. viscosum. Texas Azalea is very rare to endangered in the wild.
The obovate leaves are up to 2 x 1 inches in size. The foliage is deep green.
The very fragrant, white flowers, up to 2 inches wide, are borne in clusters during mid-spring just after the foliage emerges.
Hardy zones 6 to 8 in partial shade on moist, acidic, sandy or light, well drained soil. Very heat tolerant.

* photo taken on April 18 2010 @ U.S. National Arboretum, D.C.


Azalea x obtusum ( Hiryu Azalea )
A medium-size, semi-evergeen shrub originating in Japan that is a hybrid of natural origin between Azalea kaempferi & R. kiusianum.
Some records include: 10 years - 3 feet; largest on record - 10 x 14 feet ( 50 years ). It makes an excellent hedge. The foliage is bristly brown at first, quickly turning to bright green. In cold climates, the foliage turns scarlet-red during autumn.
The abundant, brilliant, scarlet-red funnel-shaped flowers, up to 1.5 inches across, are borne in trusses of 1 to 3 during late spring.
Hardy zones 5 to 9. This Azalea is extremely tough and easy to grow. Drought tolerant.

'Amoenum'
Intense purplish-pink flowers.

'Coccinea'
Very similar except for having rose-red flowers.

Azalea occidentale ( Western Azalea )
A very beautiful, spreading, dense, deciduous large shrub, native to the western U.S. ( from southwestern Oregon to southern California and possibly even the Baja Peninsula ). Some records include: fastest recorded growth rate - 1 foot; 10 years - 17 x 8 feet; largest on record - 25 x 10 ( usually half that ) feet with a trunk diameter of 4 inches.
The oval leaves are up to 4 x 1.5 inches in size. The foliage is glossy bright green above, hairy beneath; turning showy scarlet to deep red during autumn.
The very showy, abundant, very fragrant, milticolor white and light pink ( with a basal golden-yellow blotch ), broad funnel-shaped flowers, up to 3 inches across, are borne in trusses of 6 to 12 during mid-spring as the foliage emerges. This Azalea also comes in forms with flowers that are yellow, orange-pink, red and pink.
Hardy zones 5 to 8 in partial to full shade. It does NOT like hot summers or alkaline soils.

* photo taken by Jean Pawek @ CalPhotos

* historical archive photos

Rhododendron pentaphyllum ( Nikko Azalea )
A deciduous, slow growing, large shrub to small tree, reaching a maximum size of 20 x 20 feet, that is native to mountains of Honshu Island of Japan. It is similar to R. quinquefolium except for the large flattened, mid-pink flowers appear about 2 weeks earlier during the spring ( mid-spring before the foliage emerges ).
The elliptical leaves, up to 2.3 ( rarely over 2 ) inches long, are borne in whorls of 5 at the stem tips. They often have a reddish margin at first when they emerge. The foliage is bright green during summer; often turning intensely scarlet-red during autumn.
The smooth bark is pale grayish-brown.
Hardy zones 6b to 8

Azalea periclemenoides ( Pinxterbloom Azalea )
Also called Azalea nudiflorum. A suckering, dense, deciduous shrub, native to dry open forests in eastern North America ( from central Tennessee to northern Ohio to western New York State to New Hampshire; south to southern Alabama to central Georgia ). Some records include: 10 years - 5 x 4 feet; largest on record - 17 x 15 feet.
The obovate leaves are up to 5 x 2 ( rarely over 4 x 1.3 ) inches in size. The foliage is bright green at first, turning to deep green in summer, then to yellow during autumn.
The fragrant, multicolored white and light pink or purple-red, funnel-shaped flowers, up to 1.5 inches across, are borne in trusses of 6 to 12 during mid-spring either just before or with the emerging foliage. The flowers have a long corolla tube and very long stamens.
Hardy zones 3 to 8 in full sun to partial shade ( tolerates full shade ) on well drained soil ( even sand ). Very hardy and easy to grow. Drought tolerant for an Azalea.

* photo taken on April 18 2010 @ U.S. National Arboretum, D.C.

* photos taken on May 7 2014 @ London Town Gardens, Edgewater, MD

* photos taken on Apr 17 2016 @ U.S. National Arboretum, DC

* photos taken on Aug 20 2016 in Olney, MD

* photos taken on Aug 29 2016 in Luzerne Co., PA

* photo taken on Apr 27 2017 in Columbia, MD

* photos taken on May 4 2017 in Harford Co., MD

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photos taken on May 10 2017 in Luzerne Co., PA

* photos taken on Apr 25 2022 in Columbia, MD

Azalea prinophyllum ( Roseshell Azalea )
A vigorous, deciduous shrub native to eastern North America ( from central Missouri to southern Illinois to northeast Ohio to western New York State to southern Quebec to Maine; south to southeast Oklahoma to southern Arkansas to central Alabama to southwest Virginia to Delaware ). It is endangered in Illinois, Ohio, Alabama, Georgia, North Carolina and New Jersey. It is absent in Indiana though likely occured there and was extirpated before being documented. Some records are: 5 years - 4 x 5 feet; 10 years - 8 x 6 feet; largest on record - 17 x 17 feet. It is found in bogs and swampy woods as well as upland ( often rocky ) woods in the wild.
The oblong leaves are up to 3.5 x 2 inches in size. The foliage is mid-green above, woolly gray beneath; turning to deep purplish-green during autumn.
The very fragrant, funnel-shaped flowers, up to 1.5 inches across, are borne in trusses of 5 to 9. They are bright pink to purplish-red ( with a dark brownish-red blotch ) and open mid spring with the emerging foliage.
Hardy zone 3 to 9 tolerating as low as -40 F, thriving in anything from sun to full shade. Drought tolerant for an Azalea and somewhat alkaline tolerant as well.
Easy to transplant.

* photos taken on May 10 2017 in Luzerne Co., PA

* photos taken on July 20 2017 in Luzerne Co., PA

* photos taken on May 8 2019 in Columbia, MD

'Marie Hoffman'
Extremely fragrant, very large, bright pink flowers.
Vigorous growing and much more heat tolerant than regular Roseshell Azalea.

* photos taken on May 8 2011 in Bel Air, MD



Azalea prunifolium ( Plum-Leaf Azalea )
Closely related to Azalea calendulaceum; this is a large shrub native to eastern Alabama and southwestern Georgia in the southeast U.S. It is endangered in its native range. Some records include: 6 years - 10 feet; largest on record - 20 x 13.2 ( average is 12 ) feet. It is usually found along ravines in moist hardwood forests.
The ovate to obovate leaves are up to 6 x 2 inches in size. The mid-green foliage turns yellowish-green during autumn.
The heads of 1.5 inch wide, intense, scarlet-red flowers are borne late spring into early summer after the foliage matures.
Hardy zone 5 to 8 ( tolerating as low as -30 F ) in sun to partial shade on moist, acidic soil. Heat tolerant. Resistant to powdery mildew.

* photos taken on July 17 2010 @ Morris Arboretum, Philly, PA




* photos taken on Apr 23 2017 @ Brookside Gardens, Wheaton, MD

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* photos taken on May 6 2024 @ Brookside Gardens, Wheaton, MD

'Late Lady'
Flowers during late summer, otherwise similar.

Azalea quinquefolium ( Five-Leaf Azalea )
. A dainty, bushy deciduous large shrub to small tree, native to central Japan. Some records include: 10 years - 10 x 6.5 feet; largest on record - 28 x 24 feet.
The rounded leaves are up to 2.5 x 1.5 inches in size. The foliage is bright green, turning to purple during autumn. The leaves are borne in whorls of 4 or 5 at the stem tips.
The pure white ( with green spots ) funnel-shaped flowers, up to 1.5 inches in length, are borne in clusters of 1 to 3 during mid-spring as the foliage emerges.
Hardy zones 6 to 8b, tolerating at least as low as -10 F. Prefers partial shade and protection from excessive wind.

'Five Arrows'
White flowers with olive-green spotting.

Azalea reticulatum
A deciduous to semi-evergreen large shrub to small tree, native to Japan. Some records include: 10 years - 17 x 10 feet; largest on record - 33 x 14.3 feet.
The rounded leaves are up to 3 x 2.5 inches in size. The foliage is deep green, turning to red-purple during autumn. It may become evergreen in mild climates. The leaves are woolly brown at first and become strongly net-veined beneath.
The reddish-purple to pinkish-purple, bell-shaped flowers, up to 2 inches across, are borne paired or borne singly during early spring before the foliage emerges. A form with very large, lavender flowers, up to 4 inches in size, has been seen in the wild.
Hardy zones 6 to 9 tolerating as low as -15 F.

Azalea sanctum ( Shrine Azalea )
A deciduous large shrub to small tree, reaching a maximum size of 17 x 10 ( rarely over 12 ) feet, that is native to southern Honshu in Japan.
The round leaves, up to 3.2 inches long, are very glossy, mid-green.
The purplish-pink ( rarely white ) flowers, up to 1.6 inches wide, emerge during late spring after the foliage emerges.
Hardy zones 6 to 8

Azalea schlippenbachii ( Royal Azalea )
A very common, open, rounded, large deciduous shrub covering vast areas of woodland in eastern Russia, Manchuria and Korea where it is native. Some records include: 10 years - 6 x 8 feet; largest on record - 28 x 20.5 feet with a trunk diameter of 2.5 inches; longest lived - 75 + years. It is among the handsomest of all Azaleas.
The oval leaves, up to 6 x 3 inches, are borne in whorls of 5 at the ends of the branches. The attractive foliage is purplish at first, turning to deep green, then to intense red during autumn.
The fragrant, white to light pink, broad funnel-shape, starry flowers, up to 4 inches across, are borne in loose clusters of 3 to 6 during mid spring with the emerging foliage.
Hardy zones 3 to 8, prefers partial shade and may even develop sun scorch in full sun. Also prone to late spring frosts esp. on open sites. Alkaline soil and heat tolerant.

* photos taken by Dr. Nick V. Kurzenko @ CalPhotos

* photos taken on Apr 23 2017 @ Brookside Gardens, Wheaton, MD

'Albiflorum'
White flowers; otherwise identical to species.

* photos taken on Apr 23 2017 @ Brookside Gardens, Wheaton, MD

'Sid's Royal Pink'
The foliage is bronze-purple at first, turning to green in summer, then to intense yellow and orange in autumn. The abundant, large flowers are intense purplish-pink.
Same growth and size as Azalea schlippenbachii.
Hardy zones 3 to 8, extremely hardy.

Rhododendron serpyllifolium ( Wild Thyme Azalea )
A compact, dense, medium-size, deciduous shrub, reaching a maximum height of 6 feet, that is native to central and southern Japan.
The very small, elliptical to oblong leaves are up to 0.8 x 0.3 inches in size. The bristly foliage is deep green above, pale green beneath.
The very abundant, dainty, rose-red flowers, up to 0.3 inches wide, are borne singly during mid-spring.
Hardy zones 7 to 9, tolerating as low as -10 F.

'Albiflorum'
White flowers.

Rhododendron serrulatum ( Hammocksweet Azalea )
Also called Azalea viscosum var serrulatum. A vigorous, deciduous, large shrub, native to the southeast U.S. ( southern Alabama, southern Georgia and northern Florida ) where it is often found in swamps. Some records include: 10 years - 10 feet; largest on record - 23 x 8 feet.
The glossy deep green foliage turns to deep red during autumn.
The very fragrant, large, funnel-shaped flowers are white to rose-pink, borne mid to late summer.
Hardy zones 4 to 9 in partial shade. Tolerant of wet conditions.

* photos taken on Aug 21 2011 @ Brookside Gardens, Wheaton, MD


* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

'White Pearl'
Creamy-white flowers with a pink tinge.

Azalea tosaense ( Fuji Azalea )
A dense, upright, deciduous to semi-evergreen shrub, that is native to Japan. Some records include: 10 years - 3 feet; largest on record - 6.5 x 10 feet.
The oblanceolate leaves are up to 1.5 inches in length.
The white to deep pink, funnel-shaped flowers, up to 2 inches wide, are borne in clusters of 1 to 6 during mid to late spring.
Hardy zones 6 to 9, thriving best in southern New England and the Mid Atlantic.

'Ralph Clarke'
Red-purple flowers.

Azalea vaseyi ( Pink-Shell Azalea )
A vigorous, upright hardy Azalea native to high elevations of 4 counties in western North Carolina. Some records include: 10 years - 5 x 3 feet ( possibly up to 10 feet in 10 yrs. ); largest on record - 23 x 23 ( rarely over 12 ) feet; longest lived - 75 years.
The oval to elliptical leaves are up to 5 x 2 inches in size. The foliage is glossy deep green in summer turning to intense scarlet-red during autumn.
The spicily clove-scented, funnel-shaped flowers, up to 2 inches wide, are borne in trusses of 4 to 8. They are white, light pink or rose-pink, with reddish-brown spotting, and are borne during mid-spring before the foliage emerges.
Hardy zone 4 to 8 ( tolerating -40 F ) in full sun to partial shade. Tolerant of flooding ( but not on heavy clay ) as well as drought and even dry sandy conditions.
It thrives especially well in climates with cool summers.

'Summer Eyelet'
A handsome strong growing shrub reaching up to 5 x 4 feet in 10 years, eventually more. The profuse white flowers borne in early summer contrasts with the glossy deep green foliage.

Azalea viscosum ( Swamp Azalea )
A moderate growing, large deciduous Azalea native to acid swamps and moist pine-oak woods in central and eastern North America ( from eastern Oklahoma to northern Arkansas to Tennessee to West Virginia to western New York State to southern Maine; south to eastern Texas to central Florida ). It is endangered in Tennessee, West Virginia, New Hampshire and Maine. Some records include: 10 years - 8 x 6 feet; largest on record - 23 x 20 ( average is 12 ) feet with a trunk diameter of 4 inches.
The obovate leaves are up to 3.5 x 1.3 inches in size. The foliage is yellowish-brown at first, quickly turning to glossy very deep green above, silvery beneath. The handsome foliage turns orange, red and purple during autumn.
The spicy intensely fragrant, white, funnel shaped flowers, up to 2.5 inches long, are borne in trusses of 6 to 12 in late spring to early summer after the foliage emerges.
The young shoots are hairy.
Hardy zone 3 to 8 in partial to full shade on acidic, moist well drained soil. It is tolerant of poorly drained soil as well as sand and also sun. Moderately deer resistant.

* photo taken on Oct 21 2014 @ U.S. Botanical Gardens, Washington, DC

* photo taken by George Pyne @ USDA-NRCS PLANTS Database

* photo taken on Aug 20 2016 in Olney, MD

* photos taken on May 27 2017 @ Meadowlark Botanical Gardens, Vienna, VA

* historic archive photo

'Betty Cummins'
Deep pink flowers, otherwise similar.

'Weston's Sprarker'
A hybrid that included A. viscosum. It reaches up to 6 x 6 feet in 10 years, eventually up to 12 x 7 feet.
The foliage is blue-green above, silvery beneath. The leaves turn to deep red during autumn.
Th fragrant, deep pink ( red in bud ) flowers appear during mid-summer.
Hardy zones 4 to 9. It is mildew resistant.

Azalea yedoensis poukhanense ( Korean Azalea )
A semi-evergreen shrub, native to Korea and Japan. Some records include: 10 years - 6.5 x 8 feet; largest on record - 6.5 x 12 feet.
It is one of the parents of the Gable hybrids.
The elliptical leaves are up to 3.5 inches in length. The foliage is deep green; turning rich orange to deep red during autumn.
The fragrant, pink-purple, double funnel-shaped flowers, up to 2 inches across, are borne in trusses of 2 to 4 during mid to late spring.
Hardy zones 4 to 8 ( tolerating as low as -30 F ) and thriving in Midwestern and eastern North America. It is more soil tolerant and less prone to phytophora root rot than most Azaleas.

* photos taken on Apr 26 2013 in Columbia, MD

* photos taken on May 1 2014 in Columbia, MD

* photos taken on May 7 2014 @ London Town Gardens, Edgewater, MD

* photo taken on May 3 2015 in Columbia, MD

* photos taken on Apr 26 2016 in Columbia, MD

* photo taken on Apr 23 2017 in Columbia, MD

* photo taken on June 25 2018 in Columbia, MD

* photos taken on Apr 25 2019 in Columbia, MD

* photos taken on Apr 28 2019 in Columbia, MD

* photos taken on Apr 14 2020 in Columbia, MD

* photos taken on Apr 22 2020 in Columbia, MD

* photos taken on May 1 2020 in Columbia, MD

* photo taken on May 4 2021 in Columbia, MD

* photos taken on May 2 2022 in Columbia, MD

* photos taken on Apr 20 2023 in Columbia, MD

* photo taken on May 6 2021 in Columbia, MD

* photos taken on Apr 18 2024 in Columbia, MD

* photos taken on Apr 22 2024 in Columbia, MD

'Alba'
White flowers, otherwise identical to the species.

'Pink Discovery'
Upright in habit, with abundant, intense mid-pink flowers.
Hardy zones 4b to 8 ( tolerating -25 ).