Remarkably floriferous, with their beautiful, attractive evergreen or deciduous foliage, the azaleas are the stars of shade gardens.
Beautiful in spring as in summer, fall, and winter, these essential acid-loving blooming shrubs of the heath family ensure a very flowery spring and early summer each year, with their profusion of large, delicate flowers sometimes exhaling a sweet fragrance.
Native to mountainous regions of Europe, Asia, and North America, Azaleas ( Azalea syn. Rhododendron ) are small to medium-sized evergreen, semi-evergreen, or deciduous shrubs that belong to the genus Rhododendron of the vast Ericaceae family. There are more than 50 wild species, and nearly 8000 varieties of Azaleas come into existence due to hybridization.
Native to Asian countries such as Japan, Evergreen azaleas are mainly from the Tsutsusi subgenus, and deciduous or native azaleas are from the Pentanthera subgenus.
In April-May, azaleas produce a profusion of small to large corymbs composed of small flowers of various colors, ranging from pale pink to white, from carmine red to yellow or lavender, including all shades of pink.
Versatile as hell, azaleas fit into any garden design, from the smallest to the largest, whether isolated or in containers on a shaded garden.
Tall varieties are perfect for planting in beds with perennials, on the woodland edges, in Japanese gardens, in a flowering hedge, or the company of other flowering shrubs, while modest dimensions of certain dwarf varieties will make them ideal for growing in patio containers and can also find their place in a shady rock garden, in a flower bed, or on edge.
Read on to learn about the main types and best varieties of garden azaleas and their characteristics to help you discover your favorite!
What Is Difference Between Rhododendrons And Azaleas
Before reading this list, you should understand the relationship between azaleas and rhododendrons.
In this effort, geometry offers a great analogy. Azaleas and rhododendrons are like squares and rectangles. Recall from elementary school that all squares are rectangles, but not all rectangles are squares. Similarly, all azaleas are rhododendrons, but not all rhododendrons are azaleas.
In botanical terms, Rhododendron is a genus containing countless shrubs. All plants, commonly called rhododendrons or azaleas, are a part of this genus.
With this being the case, how can you tell the difference between the two shrubs?
Here are three of the most prevalent distinctions.
Notice these are not definitive statements. In truth, there are exceptions to all three of these rules. Even for a well-versed botanist, drawing a definitive line between rhododendrons and azaleas is a challenge.
No home gardener can expect to know all forms of either shrub. But that does not prevent you from forming your own preference for certain azalea species.
Let’s proceed with some azalea descriptions so you can develop your own opinion.
15 Of The Best Azalea Varieties For Your Garden
There are over 8,000 different types of azalea plants have been registered. This provides a wide variety of plant habits, sizes, colors, and bloom times for every landscape need or personal preference.
To that point, the sheer volume of azalea varieties can be overwhelming. When selecting one type for your yard, it is hard to know where to start. As you might expect, there are far more azaleas than can be covered in a single post.
But this list will help you make sense of the main types and varieties. The azaleas listed here cover a broad range of colors as well as native, hybrid, evergreen, and deciduous species.
Here are 15 of the best azalea varieties to grow in your garden.
Native Deciduous Azaleas
The hybrid azaleas are so prominent in nurseries that many people neglect to recognize the native azalea varieties.
Numerous azaleas grow freely in the wild around the world. Considering that all hybrids can trace their origins to a native species, it makes sense to begin this list with those native species.
I think you will find that these wild azaleas are attractive in their own right, though neglected. What is most impressive is that the forms and flowers of the beautiful azaleas have come about without human intervention.
But more important than aesthetics, these azaleas play a vital role in their respective ecosystems. Whether framing the banks of a river or standing at the crest of a mountain peak, these azaleas are great supporters of wildlife. Notice that none of them are lacking in color either.
1: Rhododendron arborescens (sweet azalea)
Native to the eastern United States, sweet azalea can grow anywhere from high mountain peaks to the edge of low-lying streams.
It is a noticeable feature throughout the Appalachian mountain range. Since this shrub is hardy to zone 4, it is a great option for azalea enthusiasts in colder climates.
Sweet azalea’s fragrant flowers are the inspiration for its name. They persist from mid-spring into summer and are primarily white.
While these flowers are not the showiest of the azaleas on this list, they do have a subtle two-toned coloration. They are almost entirely white, with one exception. The pistol of each flower is bright red. This shrub has a loose form and a preference for moist soil.
As a deciduous shrub, the leaves of sweet azalea turn red in autumn before they fall.
In place of the common name listed here, people sometimes refer to this plant as smooth azalea or tree azalea due to its height.
2: Rhododendron atlanticum (coast azalea)
Coast azalea also features fragrant flowers of a two-toned nature. These flowers are also primarily white but show noticeable pink hues as well.
But coast azalea has leaves that also add to the color display. These leaves are green with a heavy bluish tint, and the unique color of the leaves creates an appropriate contrast to the flowers.
Coast azalea grows to about 5’ in height but does not usually become that tall. It spreads through suckering and can tolerate more sun than other azalea varieties. However, it is very important to keep the roots moist.
If the roots cannot remain moist, then direct sunlight can scorch the leaves. If you are planting this species in your yard, make sure you do a good job of mulching.
Doing so will help the plant retain the moisture it needs. When that happens, you can expect a healthy plant showing contrasting colors in mid-spring.
3: Rhododendron calendulaceum (flame azalea)
Flame azalea is native to the southeastern portion of the United States. Many azalea hybrids claim this species as their parent. Flame azalea’s flowers are non-fragrant and shaped like funnels.
When in bloom, they can vary in color from yellow to orange to red. The leaves of the flame azalea are about 1-3” in length and take on a yellowish color in the fall.
This azalea grows wider than it is tall and does not tolerate extreme heat. Even though it is native to the south where temperatures are typically warmer than much of the United States, Flame azalea can’t survive in regions hotter than zone 7. These shrubs also prefer not to have their roots sitting in water.
One potential remedy for this is to consider building a raised bed where your flame azalea can thrive in ideal soil conditions. Other than that, make sure to plant this shrub in a filtered shade similar to the woodland slopes it calls home.
4: Rhododendron schlippenbachii (royal azalea)
Royal azalea is native to East Asia in countries such as Japan, Korea, and China. It is another option for both cold and warm climates since it can survive in zones 4-7.
It is small in stature, reaching about 3’ at maturity. Its form is rounded, with spread similar to its height.
The fragrant flowers of royal azalea bloom in sync with the leave’s emergence in the spring. The flowers are white with pink accents and can be over 3” across.
The leaves are also rather large compared to other azaleas. Their length is about 2-5” and they can turn either yellow or red in the fall.
As with many plants native to Asia, the species name is actually an homage to a European man.
Historical records indicate that a Russian named Alexander von Schlippenback was the first to bring the plant back to Europe. As such, the species name is a Latinized version of his surname.
5: Rhododendron vaseyi (pink-shell azalea)
Pink-shell azalea is unique among the azaleas for a few reasons. Most of these relate to its flowers. For instance, this azalea blooms in April before the foliage begins to grow in.
The result is an incredible surge of light pink clinging to otherwise bare branches. But the differentiation does not end there.
Unlike other azaleas, pink-shell azalea does not have a tube as a part of its flower anatomy. This alters the appearance of the flower petals.
Rather than having a clear physical connection, the petals of pink-shell azalea are almost entirely separate from one another.
The similarity of azaleas can make identification challenging. This small detail can help in identifying pink-shell azalea amongst all its relatives.
This azalea can also grow to be almost 15’ tall. While it is large for an azalea, the branches remain thin. Their delicate nature produces an open and irregular form with limited density even after the leaves grow in.
When planting pink-shell azalea, remember that it prefers moist soil to the point where it is intolerant of drought-like conditions.
6: Rhododendron Viscosum (Swamp Azalea)
Swamp azalea lives in a large area covering most of the eastern United States. The range is so broad that this shrub grows in both Maine and Florida. It is a rounded shrub that can tolerate standing water from time to time.
This is supported by the fact that swamp azalea grows naturally in low lying areas where water collects.
The upside of this trait is that swamp azalea is much more resistant to root rot compared to other azalea varieties.
Swamp azalea has flowers that are white, fragrant, and tubular. They bloom later than most native azaleas in May and can remain on the plant into mid-summer.
The leaves are a glossy green color in the growing season. In fall they can transform into one of a few colors. Among these color options are orange and purple.
7: Rhododendron Cumberlandense (Cumberland Azalea)
People often confuse Cumberland azalea with flame azalea. This is because they can live in a similar range and have similar flowers.
So, let’s point out a few differences. Cumberland azalea and flame azalea both have orange flowers.
However, the Cumberland azalea’s flowers are usually smaller. They also bloom later in the year than flame azalea and have less color variation.
Cumberland azalea is named as such because it hails from the Cumberland region in Kentucky.
But it can grow anywhere from Georgia to North Carolina. Regardless of which state it lives in, Cumberland azalea tends to grow on exposed slopes and mountain tops.
In residential settings, consider planting this mid-sized shrub as a specimen. With the right amount of shade and soil moisture, Cumberland azalea will add an orange accent to your garden in summer.
The massive amount of azalea varieties results from frequent hybridization over the centuries.
This has occurred to such an immense degree that there are thick books dedicated to azaleas alone. But even these large catalogs fail to cover all of the azaleas in existence.
Horticulturalists recognize many separate azalea hybridization groups. And each group contains many varieties. ENCORE is one of the most renowned azalea hybridization groups. Robert E. “Buddy” Lee created this group to feature a specific characteristic.
A normal azalea blooms once in the spring. An ENCORE azalea has the potential to bloom in spring, then bloom again later in the season. This aspect of ENCORE azalea has made them readily available in nurseries.
Because of the significant impact of ENCORE azaleas, the first few hybrid versions listed here are from that group.
Following these are a number of hybrids from other groups. There are many more hybrids for you to explore.
But these azaleas are listed here because they represent multiple colors and characteristics.
8: Rhododendron ‘Conlee’ AUTUMN AMETHYST (autumn amethyst encore azalea)
Unlike many of the azaleas, both native and hybrid, autumn amethyst is an evergreen shrub. It also has foliage that is much more dense than other azaleas.
In winter, this foliage can turn brown and die off when experiencing extreme temperatures. Keep in mind that this azalea can be slightly less cold tolerant than others which are hardy in zone 4.
Autumn amethyst developed from another azalea known as Rhododendron ‘Karen’ and has deep purple flowers. These flowers are small, about 2”, but they cover the majority of the plant in April and May.
They also attract many pollinators such as bees, butterflies, and hummingbirds. In my experience, their color combines well with border forsythia. The bold contrast of purple and yellow is a robust sign of spring.
9: Rhododendron ‘Robles’ AUTUMN LILAC (autumn lilac encore azalea)
Another popular option from the ENCORE group is autumn lilac. Compared to the flowers of autumn amethyst, autumn lilac’s flowers have a lighter color.
As the name suggests, they are similar in hue to the flowers of the common lilac. The bloom time is similar to autumn amethyst with flowers emerging in April and remaining through May.
Autumn lilac is a good option for those in warmer regions who desire an azalea on the smaller side. This species survives in zones 7-9 and grow to be 2-3’ in both height and spread.
Caring for autumn lilac is also simple as it has growing requirements common among all azaleas.
10: Rhododendron ‘Roblez’ AUTUMN FIRE (autumn fire encore azalea)
Until now, those with a preference for deep red flowers may have believed that azaleas have nothing to offer them. This is far from the case. The ENCORE series as a few red flowering varieties. Among the best options is the autumn fire azalea.
This azalea not only has a dark red flower, but that flower also persists longer than any other.
After blooming in spring, the autumn fire flower remains on the plant all the way into fall. It is also hardy across a few of the warmer hardiness zones.
These two characteristics have kept autumn fire on the market for years. As a smaller shrub, it may be helpful to plant them in groups. This will create a larger showing of red petals through the growing season.
11: Rhododendron ‘Robleg’ AUTUMN ANGEL (autumn angel encore azalea)
Autumn angel is a more recent addition to the ENCORE group. Similar to autumn fire, autumn angel has flowers that remain throughout the majority of the growing season.
But there is a stark visual difference between the two varieties. Where autumn fire is a strong red color, autumn angel is a pure white.
These white flowers are set against dark evergreen foliage. This foliage keeps autumn angel attractive in winter, and creates a juxtaposition for the rest of the season.
For more contrast, consider planting autumn angel and autumn fire together. The vibrance of the red and white flowers will be sure to catch your eye for months on end.
12: Rhododendron indicum ‘Formosa’ (Formosa azalea)
Formosa azalea originates in India. However, today it is one of the most popular azaleas in the American south.
This popularity is due to a number of benefits that Formosa azalea possesses. The most immediate benefit is visual.
When in bloom, the Formosa azalea is entirely pink. This is possibly the most profuse and consistent bloom of the azaleas.
The Formosa azalea is on the larger size. At maturity, it can reach 10’ in height and spread. If you are planting one of these shrubs in your yard, make sure you give it enough space. It helps that the Formosa azalea responds well to pruning.
So, in the case that it does outgrow its living area, you should be able to cut it back without issue.
13: Rhododendron ‘Golden Lights’ (golden lights azalea)
Golden lights azalea is another deciduous azalea. Like the pink-shell azalea, this shrub blooms before the leaves arrive.
Even though the flowers are small, they are so numerous that this shrub truly stands out in the springtime landscape.
Add the fact that the flowers are a bright orange color, and it is hard to miss this plant.
Golden lights azalea developed in Minnesota as a part of the Northern Lights azalea group. This specific species is very cold hardy.
It can live in zone 3 and survive temperatures around -40 degrees Fahrenheit. In this context, golden lights can add some much-needed color to the landscape.
14: Rhododendron ‘Girard’s Rose’ (Girard’s rose evergreen azalea)
Girard’s rose is a small upright evergreen azalea variety that rarely reaches 3’ in height. Like many hybrid azaleas, this shrub is multi-stemmed. Over time, the spread will eventually match the height.
This azalea is one of many that the Girard Nursery of Ohio has created. It features abundant flowers that gather in pink clusters in spring.
The leaves are evergreen, but they do show a shift in color. In the summer they are a dark green, typical of many azaleas. In winter they can turn red and orange as the temperature drops.
15: Rhododendron x ‘Stonewall Jackson’ (Stonewall Jackson azalea)
Stonewall Jackson Azalea is part of what is known as the Confederate Series of azaleas. Dodd & Dodd Nursery developed these hybrids by crossing Rhododendron austrinum and Rhododendron x ‘Hotspur Yellow’.
Their goal was to create an azalea that could thrive in the hot southern climate. Many of these azalea varieties are named for prominent leaders of the confederate army.
Stonewall Jackson azalea is a deciduous variety. It has large funnel-shaped flowers. The color of these blooms is a bright orange that is similar to flame azalea.
As long as this plant has some shade and moisture in the soil, it is a relatively low maintenance shrub.
Embellishment is common in plant description. But this is not the case for azaleas. These shrubs live up to all the lofty praise that plant lovers give to them.
Their blooms come in many colors and their sizes and shapes vary, allowing them to fit into many diverse planting designs.
Hopefully, you will find an azalea on this list that pleases your eye and can survive in your yard. If not, there are a few thousand more options at your disposal.
John Haryasz is a writer with a background in landscape architecture. His education includes a Bachelor of Science in landscape architecture from UMass, Amherst with a minor in psychology. Following graduation, John worked in a small landscape architecture office. In this role, he led many successful projects in Berkshire County, MA. After a few years, John began offering freelance design services. He has since produced designs for projects across the country. As a writer, John aims to share knowledge while promoting engagement with the outdoor world.