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How to Plant and Care For Azaleas

One spring we visited Calloway Gardens in Pine Mountain, Georgia, just as the azaleas were at their peak.I have never forgotten the swaths of candy colored shrubs that blanketed the woodlands. Since then I have dreamed of a similar effect in my own garden, although on a much smaller scale! 

I am speaking of azaleas in this post, but the planting and care of rhododendrons is very similar. Azaleas and rhododendrons are all in the genus Rhododendron, with thousands of named selections. All azaleas are rhododendrons, but not all rhododendrons are azaleas! It is fairly easy to tell the difference. Generally, rhododendrons have much larger, leathery leaves. Many rhododendrons will not grow well in the sub-tropical southeastern US, while azaleas, which love warm air and humidity, can flourish here as well as in the Middle and Upper South. Depending on the variety, azaleas will grow in USDA hardiness zones 5-8.

Azaleas blooming April, 2014 in my front garden

While iconic images of the Deep South often include azaleas, these plants are not necessarily easy to grow. The secret is site selection and planting. The best site receives morning sun and afternoon shade. Too much sun will make azaleas susceptible to lace bugs. Too much shade will cause lanky growth and decreased flower production. Filtered light under tall pine and oak trees is ideal. Some azaleas, such as the Encore series, can take more sun than others. Do not plant near shallow-rooted trees that will compete for moisture and nutrients. Azaleas also need acidic soil with a pH of somewhere between 4.5 and 6. 

Moist, well-drained soil is an absolute requirement for all azaleas. If one sticks an azalea in unimproved clay soil, it will die. Azaleas have shallow, delicate roots, and they must have friable soil in order to reach out for nutrients and water. These fine roots will drown in standing water, and they also will quickly smother in hard, compacted soil. Poorly drained soil will also promote die-back due to soil-borne fungus.

Like many gardeners in my area, I have clay soil. There are two solutions to this problem. Probably the easiest thing to do is to build a berm or raised bed about 8 to 12 inches high. Fill the bed with 50 percent good garden soil and 50 percent organic matter such as pine bark, peat moss, compost or chopped up oak leaves. Plant the azalea high with one to two inches of its root ball above ground. Then pull the improved soil up to the top of the root ball, forming a mound. Mulch with about three inches of shredded leaves, pine bark or pine needles. The mulch will conserve moisture, suppress weeds, and help keep the shallow roots cool during the hot summer. The mulch should not actually touch the azalea but should be applied like a wide doughnut around the stem. Kurume azalea 'Snow' grows in my front garden.

To plant an azalea directly in the ground, dig a hole at least a foot deep and about three times as wide as the root ball. Fill the lower half of the hole with a mixture of 50 percent native soil and 50 percent organic matter. Place the azalea so that one to two inches of its root ball is above ground. Then fill the remainder of the hole with organic matter. Pull the organic matter up to the top of the root ball, forming a mound, and mulch with about three inches of shredded leaves, pine bark or pine needles. As mentioned above, the mulch should be applied so that it does not actually touch the azalea's stem.

Be sure to loosen the roots and water the azalea before planting. If root bound, use a sharp knife to make several vertical cuts around the perimeter of the root ball. Then gently loosen the roots as much as possible.

Once planted, slowly and thoroughly water. Continue to water the azalea two or three times a week until the roots are well-established. This is why I like to plant azaleas in the fall. I rarely have to water them once our winter rains begin. Soil here in the Deep South does not freeze, so the roots have winter and spring to establish themselves before the stressful heat of summer arrives. Azaleas need consistent moisture, about one inch of rain per week during the hot summer. If nature doesn't provide it, the gardener must. But remember: too much water can be just as harmful as too little! Azaleas will absorb water through their leaves, as well as their roots, so overhead watering is beneficial. It is best to water in the morning so the leaves dry by afternoon. Damp leaves in the evening hours can promote growth of fungus.

Azaleas in rich, acid soil require little or no fertilizing. If the pH of the soil is too high, the leaves will demonstrate chlorosis, or yellowing. If needed, cottonseed meal or a fertilizer for acid-loving plants should be applied after flowering has finished in the spring. 

Azaleas are more attractive if allowed to grow into their natural shape, rather than sheared into tight balls, which is the habit of many who plant these as foundation shrubs.The brilliant orange Kurume azalea on the right has been growing in my garden for many years. At about four feet tall, it needs minimal pruning.To avoid cutting off next year's blooms, lightly prune by snipping off spent flower stalks in spring just after blooming has ended. This is also a good time to apply fresh mulch. Azaleas can be rejuvenated by drastic pruning, down as far as one foot of the ground. Do this in late winter or early spring, but remember you will lose the spring blooms. 

Both adult lace bugs and their immature form, called nymphs, damage azaleas by sucking sap from leaves. Leaves develop a grayish cast with a speckled or stippled appearance. If damage is severe, the leaf will appear white and will drop early. The insects feed on the underside of the leaves, so close inspection of the underside will reveal shiny black bits of insect droppings. I thoroughly spray my azaleas with horticultural oil, five tablespoons per gallon of water, in early spring as a preventative against these and other insects that may afflict azaleas. If harmful insect populations are allowed to grow, stronger insecticides may be required.

A butterfly enjoys the nectar from my 'George L.Taber' azalea, a Southern Indica Hybrid.There are many varieties of azaleas, and they all are attractive to hummingbirds, butterflies and other pollinators. Some grow low to the ground, and some will grow up to 25 feet. Choices include exotic evergreen azaleas and native deciduous azaleas.These native azaleas are growing at John's Native Gardens near Scottsboro, Alabama. Their willowy, upright forms look best in a natural setting.By choosing different types of azaleas, including the re-blooming Encore varieties, one can experience their blooms from spring through fall. If well planted and cared-for, these beautiful shrubs will return the investment many times over. The deciduous native azalea 'Florida Flame' has glowing orange blooms that light up my woodland garden in April.

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Reader Comments (19)

Yes, azaleas are difficult to grow. So much so I avoid them entirely. It was a pleasure to see all of yours grown so well. I am always amazed to see orange ones, They aren't even sold out here. A nice treat. Thank you.

March 15, 2015 | Unregistered CommenterJane Strong

How nie to see all these beautiful colors !!
Thanks for sharing your fantastic photos !

March 15, 2015 | Unregistered CommenterEla

I love azaleas, although I have none in my current garden. I did grow a few in my former cooler, shadier garden but with the dry conditions and drought I just can't bring myself to put them in here. I miss them though! For now, I'll content myself with enjoying them in your photos.

March 15, 2015 | Unregistered CommenterKris P

Azaleas bring such colour to the garden, they are such wonderful shrubs if you have the right soil. Fortunately we have, so are able to have a few to brighten the garden during April/May. Your photos show them off beautifully and they look wonderful in your woodland.

March 15, 2015 | Unregistered CommenterPauline

I love when Azalea season comes and every old shack in the county becomes a wonderland of bright color with azaleas the size of a minivan. We're starting to see a few scattered blooms opening and Dogwoods are opening, too.

The difference in Rhodies and Azaleas also has something to do with differening number of stamens, but I forget how many.

March 15, 2015 | Unregistered CommenterNell Jean

Deb, I am so happy to read this as I was just plotting and planning on adding azaleas to my gardens in a few weeks. After reading this, I will have to reconsider my plans! I may be the only gardener in GA without azaleas, but I will persevere! xo

March 15, 2015 | Unregistered CommenterChristi {Jealous Hands}

I'll never forget a trip to Virginia one year when the Azaleas and Rhododendrons were blooming. It was incredible! Many people in Wisconsin grow Azaleas. And my mother even kept a specimen Rhododendron plant alive in Northern Wisconsin--through many, many winters and several moves. But, they're so much larger and stunning in the south! Good to know how to care for them, though. I might have to add one at some point. They are so beautiful!

March 15, 2015 | Unregistered CommenterBeth @ PlantPostings

Of all the plants that I miss the most from my previous Rain forest climate...it's the colorful burst of normally green shrubs covered with blossoms. What a beautiful sight for sore gardener's eyes...


March 15, 2015 | Unregistered CommenterJen@Muddy Boot Dreams

It is fantastic to see groups of azaleas flowering together, the butterfly image is gorgeous.

March 15, 2015 | Unregistered CommenterKaren

Very informative excellent post. your images are gorgeous as always.

March 16, 2015 | Unregistered CommenterChristina

Oh these gardens are glorious! The azaleas in bloom are so beautiful and you have captured them so well. Thank you for sharing these wonderful gardens with us! They give hope that spring is in the way.

I went to Calloway October of 2013, it was beautiful but not like these pictures.

March 16, 2015 | Unregistered CommenterJanie

I very much like spring when azalea and rhododendron are in bloom. PA has many nice public gardens like Calloway highlighting those plants. Stunning displays at Calloway. I do miss living in PA. Rhododendron does well here in Niagara, but not azalea. Clay soil is one problem, but our cold winters do many of them in. People keep buying them though.

March 16, 2015 | Unregistered CommenterDonna

These are very beautiful plants, especially when planted together and healthy and in flower. They used to be very common and popular here, less so now because they often don't appreciate our hot dry weather and often as you point out the leaves get eaten.

March 17, 2015 | Unregistered Commentercatmint

I fell in love with Azaleas and Rhodies when we lived in Oregon. They don't do so well in my Utah gardens. Calloway Gardens holds a special place in my heart... 34 years ago we biked through those gardens with three little ones in tow. A beautiful peaceful place.We actually named our next son Cason, after the namesake of the gardens... Cason Calloway. Thanks for the trip down memory Lane! So nice to visit you again. Been away for a long time.

March 17, 2015 | Unregistered CommenterCarolyn

Great post! I've been to Calloway for their Christmas light show, which was spectacular, but I've heard the spring azaleas are amazing! Now that I'm up North, everyone plants rhododendron, and I don't see azaleas very often. I did plant several in my own yard, but made the mistake of planting them near the base of our best sledding hill. One of the kids took one of them out completely, and I'm not sure if the other two will make it or not :)

March 17, 2015 | Unregistered CommenterIndie

Beautiful photos! I love both rhododendrons and azaleas and have both in my garden where they have great growing conditions. The 3 I have flower at different times so I have flowers from February to June :-)

March 17, 2015 | Unregistered CommenterHelene

I absolutely love azaleas but they do not love my garden....I so wish I had more acidic soil so they would be happier here. I have tried to amend the soil but it didn't work...perhaps I can build a berm and try again.

March 18, 2015 | Unregistered CommenterDonna@Gardens Eye View

I prune my azaleas into tight semi-spheres. Because I want a Japanese style garden. But I must admit that your orange Kurume azalea looks much better then my azaleas. And I never see butterflies on my azaleas ;-( Thank you for all the useful information.

March 19, 2015 | Unregistered CommenterDenise

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