If your perception of rhododendron varieties is limited to broadleaf evergreens with pale purple blooms, it’s time to take another look. Rhododendrons come in almost all shapes, sizes, and colors and suit many growing conditions.
So, perhaps you consider adding a few of these easy-care shrubs to your landscape. Once you plant them and they are established, it’s hard to find a more reliable landscape specimen. Here are 21 easy-care rhododendrons that will beautify your yard for many years.
CONTENTS – In this article, you will learn all about the rhododendron varieties that will fill your yard with colorful blooms, along with how to care for them:
- About Rhododendrons (Rhododendons vs. Azaleas)
- Landscape Uses for Rhododendrons
- How Hardy Are Rhododendons?
- Rhododendrons, Big and Small
- Popular and Unique Rhododendron Colors
- Care and Maintenance of Your Rhododendrons
- Common Rhododendron Problems
- Where to Buy Rhododendron Plants
- 21 Best Rhododendron Varieties
- Final Thoughts on Rhododendron Varieties
About Rhododendrons
The name “rhododendron” is based on the Greek word rhódon, which means “rose,” and dendron, which means “tree.” It’s easy to see why this “rose-tree” might have been named, with its colorful blooms and branches.
It’s also easy to understand why rhododendrons are a landscape favorite.
Most rhododendrons are shade-loving evergreens with large, oval, leathery leaves. Rhododendron soil should be acidic and humus-rich soil with good drainage and even moisture. But you’ll also find varieties below suited to different growing conditions, including sunny and dry gardens.
Rhododendrons vs. Azaleas
The are sometimes confused with Azaleas, which are a sub-species of Rhododendrons. Azaleas tend to be smaller and tolerate more sun, while most rhododendrons do best in shade or part-sun.
Another difference between rhododendron is how they flower.
In the spring or summer, Rhododendrons are covered with showy flower clusters called “trusses,” composed of many bell shaped blossoms.
Azaleas do not flower in clusters; rather, they bloom along the branches.
Rhododendrons belong to the same family as Heather and Heath’s (Ericaceae). They are native to all parts of the world, excluding South America and Africa.
Azaleas are a sub-species of Rhododendrons.
Those native to North America include Rhododendron Maximum (the Rosebay), R. Catawbiense, R Carolinian, and R. Minus.
Including Azaleas, there are some 800 rhododendron species and 10,000 named varieties!
Fortunately for home gardeners, Rhododendrons come in many shapes, sizes, and colors and tolerate a wide range of growing conditions. This versatility is one of the reasons they are so popular.
Now that you are more familiar with this garden favorite, let’s talk about how you might use Rhododendrons in your own landscape.
Landscape Uses for Rhododendrons
Rhododendrons are an excellent choice for any number of landscape design. One added “bonus“ is they add year-round interest to a garden.
They are ideal for woodland settings, benefiting from the acidity of fallen pine needles.
They also standalone beautifully as dramatic specimen plantings.
When massed, rhododendrons in a border effectively guide the eye to focal points or define the broader landscape areas and outdoor spaces.
And miniature rhododendrons make wonderful additions to rock Gardens, the smaller garden, or as border plants.
One of the things I love about rhododendrons is that they bloom reliably in the spring and summer. If you travel a lot or are a winter snowbird, they are such a vibrant welcome home!
Hardiness Zones for Rhododendrons
In general, Rhododendrons tolerate USDA Hardiness Zones 4-7. Some varieties will tolerate conditions as far north as Zone 3, and south to zone 9. There are a few that are hardy only from Zones 7-9.
Most prefer shade, but there are a number of varieties that thrive in full sun.
One easy way to determine a particular Rhododendron variety’s sun tolerance is with this garden saying: “the smaller the leaf, the more sun the variety can tolerate.“
Even so, make sure you check each rhododendron variety’s hardiness when you buy it.
Rhododendron Sizes
Rhododendrons vary considerably in size, depending on which variety you pick.
In the home garden, they range from miniature and dwarf varieties that are only a few inches tall to varieties reaching 12 feet and more.
Some rhododendrons native to southeast Asia reportedly reach 80 feet tall. That may be because many rhododendron varieties live to be hundreds of years old.
This size range makes it easy for you to find exactly the right rhododendron that fits your need in the landscape.
Color & Fragrance in Rhododendrons
Rhododendrons bloom in a whole spectrum of colors.
In addition to purple, pink, and white Rhododendron flowers most often seen in landscapes, you’ll also find beautiful shades of yellow, near-blue, salmon, orange, apricot, and scarlet red.
Blooms on rhodies typically last for about three weeks in the spring.
But, if you include a few different varieties in your garden design, it is possible to extend the rhododendron bloom time of Rhododendrons from April to July.
This makes them a perfect complement to the ever-changing concert of your perennial garden.
Most Rhododendrons don’t have much of a scent. However, there are a few that perfume the air with fragrance in addition to their visual impact.
No matter which color or fragrance suits your taste, a single truss snipped from the branch makes a wonderful bouquet indoors.
Care and Maintenance of Your Rhododendron
When compared to other showy beauties in the garden like peonies and roses, rhododendrons are very low maintenance and relatively trouble free. Like any specimen in your garden, healthier plants will be more resistant to problems.
Therefore, follow these tips in mind when caring for your rhododendron so it will thrive.
Fertilizing Rhododendrons
In early spring before bloom time, you can fertilize the base of rhododendrons with a high nitrogen, high phosphorus fertilizer that contains aluminum sulfate. Most gardeners use Holly Tone.
Doing so stimulates bud and root development.
Fertilize again in late fall, but you’ll want to instead use a high-nitrogen fertilizer, as frost will damage any new bud growth. Or, simply add compost, bark or straw around the base at this time of year.
You may also mulch rhododendrons throughout the year with pine needles, oak leaves, or woodbark to help increase the soil’s acidity.
Tip: Do not cultivate around the plant, as rhododendron roots are shallow and could easily be damaged in the process.
Should You Deadhead Rhododendrons?
Although it’s not required, deadheading or removing spent rhododendron blooms will allow your plant to put energy toward growth rather than toward setting seed. This is true of most plants in the garden. It also tidies up.
You’ll want to deadhead immediately after your Rhododendron blooms, as new buds set soon afterwards.
Deadheading also ensures you will enjoy the maximum number of blooms the following flowering season. That said, it becomes quite labor-intensive if you have a number of rhododendrons.
So, don’t sweat it if you choose not to deadhead. Many gardeners do not bother with deadheading Rhododendrons and find the bloom is consistent from year to year.
At minimum, you’ll want to remove any spent blooms that have fallen to reduce the chance of inviting disease.
Water Rhododendrons
Rhododendrons require even water throughout the growing season.
Average rainfall generally supplies the necessary water for established plants. But if the season is dry, you will notice the leaves curl up. This is how the rhododendron attempts to conserve water.
So, during dry spells, you’ll want to provide a thorough watering torhododendrons to prevent this from happening. It’s also a good idea to water your rhodies one last time in late fall.
And, don’t be alarmed when the weather is cold in winter if you notice the rhododendron’s leaves curling; conserving moisture during cold spells this way is normal. In fact, it’s one way to recognize that the temperature outside is below freezing!
Some gardeners apply an anti-desiccant (anti-drying agent) to help a Rhododendron conserve water. This waxy coating applied by spray helps the plant conserve water and prevent winter injury.
You don’t want to apply an anti-desiccant too early, though – that will cause damage to the plant. Just follow the instructions on the product you choose. (Personally, I have never found the need to use an anti-dessicant.)
Rhododendron Trimming & Pruning
it’s never a good idea to drastically prune a rhododendron – although I have friends who’ve unwittingly cut theirs to the ground and the plant made a full recovery. (Phew!)
Remember that flower buds develop in the fall and swell in the spring. So if you must prune, do it right after bloom time. (The exception to this is evergreen azaleas, which need pruning after they bloom through August to maintain their size and set the most flower buds.)
You’ll want to remove deadwood and cut stray branches from time to time, even though it may sacrifice some blooms.
If you find a particular Rhododendron looking “leggy,“ you can plant shorter varieties in front to conceal the bareness. Or, you can capitalize on the graceful silhouette as a start to a tranquil Japanese garden.
Rhododendron Problems
Pests and Disease
However, they can have a few pests and diseases you’ll want to watch for.
While not particularly prone to pests, rhododendrons may suffer from:
- Borers
- Weevils
- Japanese Beetles
- Lace Bugs
In addition to a few pests, you want to watch for disease.
For instance, in an exceptionally wet spring, yellowing, spotted leaves may be signs of fungal disease. Allow the leaves to fall from the rhododendron then remove them from the area.
Chances are the fungus will run its course with minimal effect on the rhododendrons health. If drastic measures are required, remove infected parts with pruners, sanitizing with alcohol between cats.
Early detection is the first step toward effective treatment of Rhododendron pests and diseases. Go ahead and consult your gardening encyclopedia or a trusted online source to determine the best approach to managing these pests.
Whenever treating your garden for pests and disease, consider using organic alternatives over toxic chemicals when possible.
And remember that healthier plants will be more resistant to problems.
Plant Stress
Here are a few of the more common signs of stress in rhododendrons when you’ll want to evaluate the rhododendron growing conditions.
- Curling leaves and wilting may be due to insufficient water.
- Conversely, leaves that yellow may be a sign of poor drainage and root rot from too much water.
- Leaves that bleach or burn in the centers may indicate too much sun.
- Exceptionally leggy plants with few blooms may mean too little sun.
- Leaves that appear burned on the perimeter may mean you’ve planted your rhododendron in a location with harsh winds.
The good news is that most of these stresses to the plant can be avoided with proper care and planting, or simple adjustments.
Sources | Where to Buy Rhododendron Plants
Your local nursery or garden store will likely carry the more popular rhododendron varieties.
If you’re looking for information about specific varieties, contact your local chapter of The American Rhododendron Society or the Azalea Society of America. They offer a list of direct to consumer nurseries where you can buy Rhododendrons online.
Now, here are 21 easy-care rhododendrons that will beautify your yard.
Rhododendron Varieties: 21 Easy-Care Beauties
This is what’s great: there is a “rhodie“ for every garden.
These 21 rhododendrons are just a starting point that demonstrates the options you have to meet your garden needs.
With 10,000 name varieties, choices abound!
Dwarf Rhododendron Varieties
- R. racemosum – grows 6 inches (15 cm) high, pink flowers
- R. ‘impeditum’ – a compact, 15-inch (40 cm) purple-flowering dwarf, perfect for shady rock garden
- R. keiskei – 2 feet (60 cm) high with bright yellow flowers, red leaves in autumn, and spreads to 4 feet wide
Largest Rhododendron Varieties
- R. vaseyi – Pink-Shell Azalea, up to 15 feet (4.5 m.) wide, light pink flowers, deciduous
- R. maximum – Great Laurel or Rosebay, typically 12-15 feet (3.5-4.5 m.), but can reach 40 feet (12 m.) in native habitat. Largest leaves of all native rhodies, large white Rhododendron blossoms
- R. prunifolium – Plum Leaf Azalea – to 8-20 feet (2.4-6 m.), orange red to bright red flowers
Drought tolerant
- R. Carolinianum – Carolina Rhododendron, small pink flowers that attract hummingbirds, grows 3-6 feet (1-2 m.).
Bog tolerant:
- R. canadensis rhodora – dark green leaves, hairy gray-green underside, violet purple flowers, 3-4 feet tall
Full sun tolerant
- R. ‘Christmas Cheer’ – Shades of pink to white flowers, blooms extend up to 2 months, hardiness zone 7-9
- R. ‘Hallelujah’ – vibrant rose-red flowers, narrow grayish-green foliage
Fall foliage
- R. x ‘P.J.M.’ – foliage turns mahogany, lavender flowers in spring
- R. ‘Gerards Hot Shot’ – foliage turns orange-red in autumn
Early-season
- R. ‘Rosa Mundi’ – palest pink flowers in very early spring, hardy zones 7-9
- R. ‘Elsie Frey’ – white with pink thrush, golden throat, early spring, also fragrant nutmeg aroma!
Late season
- R., Azalea ‘Red Fountain’ – dark red orange flowers around July 4
- R. ‘Abba’ – blooms into July
Fragrant
- R. ‘Snow Lady’ – lightly fragrant white flowers with black stamens
- R. ‘Fragrantissimum’’ – heavily scented, frilly white flowers, bright yellow throat and a blush of pink
Unique Rhododendron Colors
- R. ‘Trinidad’ – wavy lobes of cream with red edges;
- R. ‘Top Banana’ – brick-red buds open to bright yellow
- R. ‘Blue Baron’ – sky blue flowers, bronze foliage in autumn
Final Thoughts on Rhododendron Varieties for Your Home
Rhododendrons are such a versatile plant for the home landscape. They are hardy, beautiful, and low-maintenance. After reading this, you’re sure to find one (or more!) that is a perfect match for your garden.
And if you’re wondering what are good companion plants for rhododendrons, click here for for gorgeous spring flowering trees. Together, they will make your yard the envy of the neighborhood.
A modified version of this article first appeared in The Country Gazette as “A Rhododendron for Every Taste” by Jackie Gately.
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