How to Plant, Grow, and Care For Azaleas
Thinking of adding some Azaleas to your garden this season but aren't quite sure where to start? Azaleas are one of the most popular shrubs you can grow, behind Hydrangeas and Rhododendrons (which Azaleas are just a variety of). In this article, gardening expert and flowering shrub enthusiast Jill Drago teaches you how to plant, grow, and care for Azaleas in your garden!
Azaleas are beautiful spring blooming shrubs. They have become well loved and a staple in many home gardens for their lovely fragrance, and bright, glowing flowers. Many of us think of these flowering shrubs blooming in bold reds and bright pinks. But there are plenty of azaleas that bloom in purple, white, yellow, orange, or even a combination of these colors. Azaleas are easy to grow, and very versatile.
Almost every gardener can find a spot for one of these lovely blooming shrubs in their gardens. So if you’ve decided to grow azaleas this season but aren’t sure where to start, you’ve landed in the right place.
In this guide, you’ll learn everything you need to know about this beautifully scented shrub that has gorgeous blooms. You’ll learn all about Azalea care, maintenance, what hardiness zones they will grow in. You’ll also learn what to expect during their growing season. Ready to learn more? Let’s jump in!
Azaleas Plant Overview
Plant Type Flowering Shrub
Season Early sping to Summer
Pests Caterpillars, Beetles
Exposure Partial sun to Partial Shade
Maturity Date 5+ years
Species Rhododendron spp.
Growth Rate Slow
Soil Type Acidic, Well Draining
Native Area Asia, North America
Plant Spacing Variety dependant
Attracts Hummingbirds, Pollinators
Plant with Hydrangeas, spring bulbs
Planting Depth 2″ about soil line
Watering Requirement Moderate
Don’t Plant With N/A
Height 3-20″ feet, variety dependant
Most of the azaleas we know and love today have been hybridized from species that are native to Asia. The seeds were sent by Buddhist monks to Europe, where their hybridization began.
Azaleas made it to the United States in the mid 1800s, when they landed in South Carolina and the southern love affair began.
There are also azalea varieties that are native to the east coast of North America, typically around the Appalachian mountains. Seeds from these plants were brought to Europe, and the species were hybridized together to create the many Azaleas we get to enjoy today.
Azaleas are members of the Ericaceae family, and fall under the Rhododendron genus. This genus has around one thousand different species. It is important to remember that all Azaleas are Rhododendrons, but not all Rhododendrons are Azaleas. There are a few key differences between the two.
Azaleas vs. Rhododendrons
- All Rhododendrons are evergreen. Azaleas can be evergreen or deciduous.
- Rhododendron flowers are bell shaped, but the azaleas look like a trumpet.
- Rhododendron flowers have 10 stamens, while Azalea flowers have 5 stamens.
- Rhododendron leaves have scales, while azalea leaves have small hairs on them.
The most common methods of propagation are cuttings and air layering. Cuttings are generally the easiest and are the most commonly used method of propagation. Let’s take a deeper look at each method so you know what to expect.
Azaleas can easily be propagated from cuttings very easily. Take cuttings anytime after June from new growth. Do not choose any old woody growth, you are looking for flexible green growth at the ends of branches.
Make sure there are at least a few sets of leaves on this cutting. Strip all but the top two leaves, and cut the top set of leaves in half. This will reduce the surface area of the leaf.
Dip your cutting into some rooting hormone, and stick it into a sterile planting medium and cover the whole thing with a plastic bag. The plastic bag will create a greenhouse-type effect. Make sure the bag doesn’t touch the plant at all, it can cause burning of the leaves. Using planting stakes to prop up the bag. Rooting should take place in about two months.
Keep these cuttings indoors until next spring. At this point, you can transfer them to a larger pot or you can move them into your garden.
Layering is a simple way to propagate azaleas, and has a pretty high success rate. Start by choosing a branch that is low enough and or can be bent towards the ground. Once you have selected your branch, scrape away a few inches of the plant surface.
Cover the exposed area of the branch with garden soil, and use a rock from your garden to hold it in place. In about a year this area will have formed new roots. At this point it can be moved to its own new home in your garden.
This is another method of layering that is handy if you do not have any branches that can easily be bent to the ground. Strip away some bark from the stem, and apply some rooting hormone to the wound.
Use a handful of moist sphagnum moss to protect the wound and the hormone. Wrap this moss-covered area in plastic, or even electric tape to keep the wound water-tight.
Check on this area every month to make sure that the moss is remaining moist. Come autumn you should be finding tender roots growing from the branch. Cut the branch from the plant and pot it up. Keep it in a cool well-lit area, such as a cold frame until stronger roots have formed.
How to Plant
The best time to plant azaleas is the spring or the fall when the weather is cooler. These cooler temperatures will help to prevent transplant shock.
When you are selecting a spot in your garden for your azalea you will want a location that is protected from the wind and has partial shade. A woodland garden is a great spot for azaleas but beware of other shallow-rooted trees and shrubs that could be nearby. This will cause intense competition for all of the plants and could cause the azalea to fail.
When you remove your azalea from its container, it could be a nursery pot or burlap, you will want to gently break up the root ball. If the roots are dense, you may want to use garden snips to cut some of the roots loose from the bottom as well as the side.
When you prepare your garden, dig a hole two or three times larger than the root ball. Add compost or other organic material to the hole, especially if your soil is too sandy or dense.
Situate the azalea so the top of the root ball is two inches above the existing soil. This will help with drainage. Backfill the hole with your garden soil, and water deeply. Mulch your new planting to help the plant retain some moisture.
Hold off on fertilizing as the compost you have added will be nutrient dense and will give the azalea what it needs.
How to Grow
When it comes to growing Azaleas, there are several important factors that contribute to their growth. You’ll want to ensure they are planted in the right location, with the right amount of light and that they get plenty of water. They also have fertilizing needs to keep in mind for better blooms. Let’s look at each important factor in detail.
Azaleas can tolerate full sun, as well as partial shade. If you plant in full sun, the result will be more compact plants with more flowers, however, the flowers will not be long-lasting. Planting in partial to full shade will produce leggier plants with longer-lasting flowers.
Azaleas are shallow-rooted plants, just like rhododendrons. Mulching around the base of these plants will help retain moisture.
Azaleas require about one inch of water per week. Oftentimes rainfall will be enough to sustain these plants, but you may need to water supplementally.
If you notice that the leaves are drooping, this is a very good sign that your plant needs a drink. This is common with new transplants or mature plants that are exposed to wind or sun. Water azaleas with drooping leaves slowly and deeply and you should see some recovery in a few hours.
Just like their larger cousins, the Rhododendron, Azaleas are acid-loving plants. You are looking for a pH of 5.5-6. Plant them in well-draining soil. Keep the soil moist, but not wet; Azaleas do not like having wet feet.
Climate and Temperature
Most azaleas can be grown perennially in hardiness zones 5-9. Of course, this will vary from variety to variety. Be sure to check the plant tag when purchasing and take careful note of any planting instructions the tag may offer.
If you live in a southern climate you will want to provide more shade for your azalea than if you live in a northern climate. And as already mentioned, always plant where there is wind protection.
Because they are shade-loving shrubs, they are susceptible to some fungal diseases. Humidity can promote these diseases. When choosing your planting site make sure there is plenty of air circulation. This may mean making sure that none of your shrubs are planted too closely together, and that you are keeping in mind the full size at maturity.
Established azaleas do not need much fertilizer if any at all. If you choose to fertilize, you will want to do this in the early spring, and avoid any feedings after July. This will help to prevent overgrowth which could become a victim of winter dieback.
A basic 10-10-10 fertilizer will work, however, there are specialized fertilizers on the market targeted toward acid-loving plants.
Caring For Azaleas
Azaleas tend to be extremely low-maintenance plants that tend to take care of themselves. There are still a few important maintenance steps you’ll want to adhere to though, in order to ensure they have beautiful blooms all season long.
Pruning is best done shortly after the blooming period ends. This will help you avoid cutting off next year’s flowers. You may even opt to remove some branches while the plant is still in bloom. Don’t toss those branches, bring them indoors and enjoy them in your home.
When it comes to major pruning, this is best done early in the spring before the plant has put out too much new growth. To avoid any pruning shock, use the “one-third” rule. Remove one-third of height, width, and inner growth only.
Use clean cutting tools, and take your time. Visualize what you want your shrub to look like and make cuts that will enhance the natural shape of the plant.
When it comes to deadheading azaleas, it’s really a matter of personal preference and not required, unlike other flowering shrubs. They are notoriously easy to care for, so deadheading spent blooms really won’t do much to improve the health of your plant. Many gardeners opt to deadhead though, in order to improve the appearance of their shrub.
To deadhead, use small clean pruning shears to remove the spent bloom where it meets the plant. You can also remove the entire stem if you choose to do so. Deadheading will also increase the likelihood of bigger blooms next season.
There are over 10,000 varieties of azaleas. Here are a few tried and true classics that may be a good start for your gardens.
Delaware Valley White
This beautiful white flowering shrub has crisp white flowers that are like a breath of fresh air to any garden. This spring bloomer will grow from two to four feet high and three to five feet wide and is hardy in zones 6-9.
Gardeners in zone 5 may have some luck. Plant this evergreen azalea in partial sun to partial shade for optimum blooms. Grows nicely as a hedge along a fence or porch.
Electric Lights Double Pink
Choose this azalea if you are looking for some gorgeous pink double flowers. This pink flowering shrub is a larger azalea, growing to heights of six to seven feet. This variety tolerates full sun to partial shade, and is hardy from zones 4-7.
‘Electric lights’ would make a really nice focal point in a garden, or could be used for a taller hedge. Or you could plant this under a window where you could enjoy both the flowers and their intoxicating fragrance.
This deciduous azalea blossoms each spring with a bang. The blossoms on this shrub are a fiery orange and open at the same time it is leafing out, giving the shrub a unique spring interest.
‘Fireball’ will grow to four or five feet and is hardy in zones 5-8. Plant this shrub in full sun to partial sun, and pair it with other spring blooming plants, or evergreen shrubs such as boxwood, or inkberry.
This beautiful variety offers up gorgeous trusses of orange flowers. This variety will grow from five to six feet, and love to be planted in partial or filtered sunlight. ‘Gibraltar’ is a deciduous and upright growing, and will make a lovely foundation plant, or an illuminating plant in a woodland setting.
This is a lightly fragrant yellow flowering shrub. There is just something about a pale yellow in the springtime, it just feels right. ‘Lemon Lights’ is hardy in zones 4-8 and will grow from 4-5 feet. Plant this azalea in full sun to partial shade. This variety is nicely used as a backdrop to perennial gardens.
This Azalea has bright magenta blooms – almost a hot pink color. ‘Mothers Day’ blooms anywhere from the middle of spring to late springtime. Usually gracing the holiday of Mothers Day with some bright blossoms. It’s compact in size, growing to three feet tall. Use ‘Mothers Day’ in a mass planting if you desire a bright swath of azaleas.
Azaleas have plenty of uses in your garden, let your imagination run wild. My favorite way to use them is in a large swath, either as a hedge in front of a porch, or a big wave of color under trees.
Azaleas also make great potted plants that could be positioned on either side of a door, or around a patio.
While azaleas are typically low maintenance, pests can still be an issue. You’ll need to monitor for pests regularly, and plan to treat them as they arise. There are several pests you’ll be likely to encounter depending on your geographic location.
Scale insects look like white cottony masses on the branches of your shrubs. The white that you see is a protective casing, with a female scale insect inside feasting on your azalea while also protecting the eggs.
Scale insects prey on plants that are stressed and already unhealthy. The best way to prevent a scale infection is to keep them watered and remove any foliage or branches that appear to be infected.
Caterpillars are not picky eaters and can be found anywhere and everywhere in your gardens in the summertime. Azaleas have their own private dinners, the azalea caterpillar.
These caterpillars show up later in the summertime and have a distinct red head. Caterpillars will munch on your azalea, when they are full they crawl down into the soil and lay their eggs right at the base of the plant.
These caterpillars are social and are typically found in groups which can make control easier. Remove these insects by hand, or by using an insecticide such as Sevin.
Rhododendron lace bugs are small flying insects with lace like wings. These insects attack rhododendrons that are in full sun, and this usually happens in mid July when the weather heats up.
Lace bugs leave stippling, or small yellow spots, along the upper surface of the rhododendron leaves. The lace bugs will lay their eggs on the undersides of the leaves.
Some friendly garden pests such as spiders can help a bit with the control of these insects, although you can’t totally depend on them. Using a broad spectrum pesticide can be difficult. You will need to spray multiple times during the insect’s life span.
Another type of caterpillar, leaf miners are very small and can cause some unsightly damage to your azaleas. Their feeding sights can be small at first and will appear as yellowing of the leaf. You may later notice that the leaf tip browns and folds over. In other cases, the leaf may be yellow and drop.
Leaf miner moths are light yellow, and maybe your first sign of an upcoming infestation. These little mining caterpillars will actually hide in the leaf tissue making them difficult to control. Luckily the damage is just aesthetic. Remove any affected leaves, or crawlers when you see them.
A common pest, nematodes are microscopic worms that live in the soil. Oftentimes these worms can be beneficial against other insects.
However, nematodes can wreak havoc on your azaleas. These little worms will feed on the feeder roots of the shallow-rooted azaleas, resulting in dramatic yellowing of the plant. If the infestation is great enough, it could result in plant death.
There is no chemical control for these nematodes. Keeping your plant healthy and your garden clean is the best way to prevent these worms from attacking your plant.
Whiteflies are small white flies that look like tiny moths. Their larvae, or caterpillars, hatch and begin sucking the life out of your plant. That isn’t the worst part about whiteflies, however.
They excrete honeydew, which is a sweet sugary substance. This honeydew will attract sooty mold. Sooty mold can turn the whole plant black with mold. This mold can block sunlight from the plant, causing the plant to suffer.
Horticultural oil, such as Bonide All Seasons, is a great option for control of whiteflies on your azaleas. Be sure to follow the labeled instructions for application.
Similar to pests, these popular shrubs are also subject to a few different diseases. Most of these are fairly easy to spot and treat if seen early on. As long as they are caught early, you have a good chance of your Azaleas making a full recovery. With that being said, prevention is by far easier than treatment. Let’s look at the most common Azalea diseases.
This is a fungus that spreads via wind or water and overwinters in flower and leaf buds. This fungus causes large fleshy galls on flower petals or leaves. These galls will harden over time, and fall to the ground
Control is not always necessary here. The galls are unsightly, yes. The best way to control the azalea gall is by prevention. Remove any galls that you see on your plant. When those galls hit the ground the spores will fly free. Using neem oil on a regular basis has also been shown to be beneficial on the control of the leaf gall.
This fungus attacks only the flower petals on your rhododendrons. It will start as small brown spots on your petals that will rapidly spread.
This fungus will ruin your bloom for the year. The infected petals will fall and attach themselves to the leaves of the rhododendron, or will just fall to the ground.
The best thing you can do to prevent this fungus or at least stop it from coming back the following year is to keep your garden free from debris. Raking the fallen petals and taking them far away from your plants will be a great help.
Like any plant that resides in the shade, azaleas are susceptible to powdery mildew. This fungal disease spreads via water and is most common on shade-loving plants that receive a lot of supplemental watering.
Powdery mildew looks like white fuzzy clumps of fur on your plant. It can cover all parts of the plant but is most common on leaves and branches.
Using a copper fungicide can help to treat powdery mildew. However, keeping your garden clean of leaf litter will help the spread of the disease.
If you notice some orange or reddish spots covering the leaves of your azalea, you are most likely dealing with rust. Rust is a fungal disease that is very common in gardens. Rust can cause spots on the underside of the leaf, as well as galls and cankers on the branches of the plant. These galls and cankers are what could cause rapid decline of your shrub.
Remove any infected plant material and discard it as soon as you can. Do not add to your compost. Copper fungicide will work for this fungal disease as well.
This disease will cause one or more entire twigs or branches to die back. You may first notice all of the leaves dropping. If you scratch the bark away from the branch you will notice a reddish orange discoloration.
Twig blight can be controlled by pruning and removal of infected branches. Be sure to clean your tools thoroughly after pruning to avoid any further spread.
Frequently Asked Questions
Why are my Azalea leaves falling off?
There are two types of azaleas: deciduous or evergreen. If you have a deciduous azalea it will lose its leaves in the fall. Evergreens will also lose some of their leaves over the winter. This is because evergreens grow two sets of leaves each season, dropping the older set in the winter.
If your leaves are brown and dropping this could mean your azalea has an issue. This usually has to do with growing conditions: too much or too little water, or too much fertilizer. Check the roots to see if they are healthy, or if they are brown and have become sort of soft and mushy. If they are mushy, overwatering is the likely cause.
Why isn’t my Azalea blooming?
If you have a newly planted azalea that is not blooming, be patient. When they are establishing themselves in a garden they may need to put more energy into rooting, and take a season off from flowering.
If you have a dependable azalea that has suddenly stopped blooming there are a few things that could be contributing to this.
- Check your pruning time. It is best to prune right after blooming stops.
- If you waited too long to prune you may have snipped off some flower buds.
- Check to ensure adequate sunlight is being provided.
- They do need some sunlight to have strong flowers.
- If you planted under a tree, it may get too much shade.
- This can be fixed by pruning the tree or transplanting to a new area.
- Azaleas need phosphorus in their fertilizer to promote flowering.
- Too much nitrogen and not enough phosphorus will reduce blooms.
- A lack of moisture during the bud forming period can cause poor flowering.
- Be sure to water regularly, especially through the hot months.
Can I plant my potted gift azalea outside?
Azaleas are lovely gifts that are available at many florists. If you have received a potted azalea you may be wondering if you can plant it outside? First, if possible, try to find out what variety of you have. If you believe this azalea is cold hardy, you can absolutely plant it outside in a partially shaded area of your yard.
If you are unsure, you can always keep it in the pot and enjoy it outside. These azaleas will need to be repotted every few years. Bring them in in the wintertime, and keep them in a cool area of your home. Keep these potted plants watered, and check on the roots every few months to make sure that plant is not becoming root bound.
Start your spring out with an explosion of color, and give your garden some Augusta National vibes by adding in some gorgeous azaleas. They are simple to care for year after year. There are thousands of varieties that come in different shapes and colors. There really is a perfect Azalea you can grow for just about every gardener!