7 Best Fertilizers for Azaleas

best fertilizers for azaleas

If you ever feel jealous of the vibrant, gorgeous, and colorful bush of Azalea blossomed nicely in your neighbor’s backyard, then you’re not alone.

We’re all guilty of admiring the Azaleas whenever we find them. That’s when many people start to grow their own Azalea in their backyard. If you’re one of them, then you must be wondering the best fertilizers for the Azaleas.

Well, look no further. Here is a list of the top 7 fertilizers you can use for growing Azaleas. Besides that, we’ve also discussed some important information you should know.

Should you Fertilize your Azalea?

Besides being beautiful, people grow Azalea because they’re easy to do so. Although they can be finicky, caring for them requires less effort. When it comes to fertilization, they typically do not require fertilizers for growth. But this depends largely on the soil in which it is growing.

Azaleas are acid-loving plants. This means they grow well in soil with a pH level less than 7, ideally around 5.5. Fertilizers can create the ideal growing environment and provide essential nutrients to the Azalea plant.

The macro-nutrients present in fertilizer like nitrogen, phosphorous, and potassium aid the development.

Therefore, whether or not to apply fertilizer Azalea plant depends on the soil and any special needs of the plant. Ideally, you should get the soil tested for pH level. And only apply fertilizers only if the pH is above 7. The type of fertilizer you employ will also affect the plant’s development.

What Does Growing a Healthy Azalea Requires?

Planning. That’s the first thing you’d need to grow Azalea successfully. As mentioned previously, Azalea calls for an acidic soil of between 5.5-6 pH. Also, the soil should be humus-rich and well-drained. Dry and alkaline soil is an Azalea killer.

A well-drained soil requirement also means you should plant the water regularly. Another reason to water Azaleas is they have shallow root systems that can extend 4-6 inches.

Daily or every other day is the ideal frequency for watering. But it depends on the weather and size factor too. The bigger the surface area, the more frequent watering you’d have to do. You can also try mulching to increase soil moisture.

To prepare the best mulch beds, cultivate the soil with organic fertilizers or compost. Things like leaves, grass, and straws are great for mulching. The water content of these organic matters will help the soil retain moisture. You’d also have to remove weeds and extra branches.

For growing Azalea, you must take care of lighting conditions. Azaleas are shade plants, which means they grow best under shades. Very rarely, they would require direct sunlight.

Temperature is an important consideration too. Some varieties can withstand chilling wintry days, while others can’t. A few species are susceptible to winter burn. Therefore, you must take precautions to avoid frozen ground or direct wind exposure.

Just like winter burns, some species are susceptible to summer burns. So a strict no to direct afternoon sun, but morning sunlight is recommended as it can accelerate photosynthesis.

Finally, pruning from time to time is an absolute must for Azaleas. With pruning, you remove unnecessary stems, buds, and branches. They’d consume the nutrients that the roots intake while offering nothing in return. The best time to prune is in the early part of summer. That’s when buds start to come out in most Azalea plants.

How to Identify Special Needs of Azalea?

While Azaleas do not have any special needs, you must identify the type of Azalea you’re growing. There are more than 800 species. So with changes in species, the growing requirement deviates, albeit not drastically. If you have a smaller area, then you’d need to draft Azaleas. Taller variants will not grow particularly well in such spaces.

You should distinguish between winter, Encore, and Evergreen Azalea. And then ensure that you’re planting the correct variant with respect to the season.

Azalea plants are usually bug resistant. That’s why they do not catch disease either. But it’s not to say they cannot. You should constantly monitor for insects like lace bugs and spider mites. Root rot and leaf spots are a possibility too. A good drainage system is a key to preventing these types of problems.

You can have leaves that are smaller than usual. Then they may turn yellow and fall down. This means the plant is suffering from chlorosis.

Another vital sign that signals nutrient deficiency is when the leaves turn a darker green. This is often accompanied by branch tips falling dead.

For treating color-related conditions, you may wish to seek expert opinion before applying anything. Fertilizers are a mixture of a lot of compounds, and not all of them will treat the condition. For example, to treat the chlorosis problem, you’d have to supplement iron. So you’d be asked to get an iron-concentrated solution or prepare iron-rich manure at home.

Nutrients Required for Azalea’s Growth

Azalea’s nutrient requirements aren’t too much different from other plant’s requirements.

Nitrogen is the foremost nutrient an Azalea plant would need. Plants use it as a major component of chlorophyll. If you’re unaware, then chlorophyll is how plants convert sugars from carbon dioxide and water using sunlight. Nitrogen is also a major component of amino acids.

To treat chlorosis, you should add nitrogen and iron to the soil.

Another important nutrient for Azalea for proper growth is potassium. The macronutrient allows the Azalea to circulate water, carbohydrates, and other nutrients through itself. Potassium also allows the plant to take up essential nutrients from the soil. Without sufficient potassium, the nutrient sufficiency of the soil doesn’t matter.

Finally, Azalea plants would need another nutrient called phosphorous. This is a vital component of a plant’s DNA, RNA, and ATP process. All these things allow Azaleas to grow.

Other than the above, there are other nutrients like calcium, magnesium, sulphur, boron, and chlorine. Each one of the nutrients has a specific role to play in plant development. Therefore, you’d have to supplement all of these from time to time to ensure the proper growth of your Azaleas.

You can get the nutrients from either homemade manure or compost or use a fertilizer. Both have their pros and cons. So you’d have to balance accordingly.

It’s advised to get a soil check done to check for the presence of these nutrients.

When to Fertilize Azalea?

You should start fertilizing your Azaleas as soon as you spot any nutritional deficiency. Some signs like yellowness, dark greenery in leaves are one sign that calls for immediate attention. You should apply a high-quality fertilizer to meet that nutritional deficiency.

If the plants are growing too slowly, then it’s a sign that you have to apply the fertilizers. This means that the plants are under developing because they’re not receiving the proper nutrients.

But you should never apply fertilizers if the plant is growing appropriately. Some growers do so to speed up the plant development, but that’s a mistake.

In the case of Azaleas, only apply fertilizers when you spot deficiencies, or you have to make the soil acidic. There are quick acting fertilizers that acidify the soil in a relatively short period of time. You should select those over slow-acting fertilizers to boost acidic content if that’s what the plant requires.

Procedure to Fertilize Your Azalea

How you apply your fertilizer depends on the type of fertilizer you’re buying. They basically come in three forms: granular, powder, and liquid. You’d have to use each type differently.

Granular is far better than powder and liquid when it comes to ease of use. You just have to spread it evenly on top of the soil to have it work. Then as you water the soil, the nutrients get absorbed. A few other granular fertilizers work differently. You’d have to prepare a solution by mixing it with water. Then apply the solution around the plants.

For powdered and liquid fertilizers, you’d have to take care of mixing proportions. This is where you need to be careful. Otherwise, they can cause fertilizer burn. Always make proportions as directed.

Depending on the area you want to cover, you will either opt for a broadcast application or a top-dress application. The former is best for larger areas, whereas the latter is best for individual plants/shrubs.

But whichever type you choose, you must first understand the pH level of the soil and environmental conditions. Over-fertilizing can hinder the growth of Azalea.

The 7 Best Fertilizers for Azaleas that we recommend

1. Espoma Organic Azalea Tone

Granular, acidic, slow-release — this fertilizer has ticked every box to be an ideal fertilizer for Azaleas. Now add onto the fact that it is organic and contains bio-tone microbes, and you can see what it’s perhaps the best fertilizer for Azaleas.

The fertilizer comes straight out of the factory of Espoma Organic. They deal in all things organic and encourage gardeners to adopt organic farming. Being organic, you do no harm to the Azalea plants or the soil.

In the case of inorganic fertilizers, the compounds make the plants dependent on them. This means, once started, you have to keep fertilizing the soil continuously. Otherwise, the plants will not grow as expected.

With this organic fertilizer from Espoma, you don’t make the plant dependent on the compounds for growth. Therefore, you can stop the fertilizing process once you’re satisfied with the growth, and the Azaleas will stay lively.

Another highlighting feature is bio-tone microbes. A proprietary blend of microbes and mycorrhizae prepared exclusively by Espoma, it provides the ideal growing conditions for the roots. They provide the necessary nutrients by creating thousands of entry points in the roots. When the root stays healthy, the other parts of the Azalea plants are likely to be healthier.

Lastly, it is slow-release and hence is ideal for most indoor and outdoor gardening. The fertilizer, once applied, will keep on delivering the necessary nutrients over a prolonged period of time.

NPK ratio is 4-3-4, thus high in the top 3 macronutrients.

If you’re just a beginner and starting out with a small bunch of Azalea plants, then this is the fertilizer to go with. There’s no reason why experienced gardeners cannot use this product. An all-around product for all.


  • Pure organic with no sludges or fillers
  • Rich in microbes and mycorrhizae
  • Granular fertilizer
  • Slow-release


  • Not ideal for use during the winter season

2. Dr. Earth 703P Organic 4 Azalea Acid Fertilizer

Dr. Earth is a popular brand among organic gardeners. This is because of the company’s commitment to a sustainable and transparent fertilizer creation process. This product is specifically designed for Azalea and Rhododendron plants.

As the label reads, “Acid Lovers,” this fertilizer is for acid-loving plants. Since Azaleas grow exceptionally well in acidic soil, this fertilizer is a perfect fit. It releases the nutrients and other matters almost immediately, thus making soil acidic within a short period of time.

Created from strict organic matters, you get a superior blend of fish bone meal, cottonseed meal, alfalfa meal, and kelp meal. Most of these come from ocean seaweed, and Dr. Earth procures only the authentic ones.

This fertilizer contains something known as “TrueBiotic.” A proprietary product of Dr. Earth, its job is to break down the organic nutrients and release them evenly into the soil. This ensures, all the roots are supplemented equally. This enhanced nutrient delivery mechanism can potentially increase the Azalea plant’s performance. Thus, you can expect bigger and brighter flowers as the yield.

The fertilizer also makes the plant drought tolerant. Because of the slow-releasing nature and multiple strains of ecto and endo mycorrhizae, it makes the soil moisture for a long time. So this is a great option if you’re growing your Azaleas in comparatively drier soil.

This fertilizer isn’t just restricted to Azaleas. You can use it for blueberries, hydrangeas, strawberries, and essentially every evergreen plant. So if you’re managing a varied garden and looking for an all-around organic fertilizer, then you can easily settle on this product.

The NPK ratio of this fertilizer is around 3-4-3.


  • Made from organic matters and ocean seaweed
  • Pro-biotic and Mycorrhizae makes Azaleas drought resistant
  • Quick-acting
  • Ideal for all evergreens


  • It might not be ideal for all Azalea variants

3. Miracle-Gro 1000701 Pound (Miracid)

Specifically formulated for Azalea and Rhododendron plants, this fertilizer from Miracle-Gro is perfect for gardeners who prefer to spray. The product comes in granular form with which you create soluble plant food.

Pour the liquid into a fill feeder jar and start spraying. Some gardeners find this form of fertilizing easy and entertaining. If that fits your persona, then this plant food is for you.

The main advantage of using liquid fertilizer is they reach the roots faster than other types of fertilizers. The solution first ionizes the nutrients before acidifying. Ions can travel faster than other molecules. This promotes quick and lasting results.

The nutrients delivered in one spraying session lasts for 1-1.5 week. For indoor plants, the frequency is every two weeks. So you do not have to work regularly either.

Coming to the ingredients, it has an NPK ratio of 30-10-10. Which means it is rich in Nitrogen. This at a competitive price of $15 for 1.5 lb. One bag of this product can easily feed 600 square feet of area comfortably.

Even though it’s concentrated liquid, the product is designed to not hurt other plants or burn foliage. This makes it a great choice for use in garden with multiple plant types.

This product was previously marketed as Miracid. So if you’ve heard a thing or two about Miracid from your friend and looking for the product, then this is the same product. Do not get confused. There’s an all-purpose plant food too from Miracle-Gro. It ships at around $6 but contains less acidic compounds.


  • It starts to work instantly
  • Plant food feeds the roots directly
  • Safe for all plants
  • Affordable for all gardeners


  • There’s a learning curve of preparing liquid with the correct proportion

4. Jobe’s Organics 9826 Fertilizer

Jobe’s Organics makes organic farming easy. And this fertilizer makes growing Azaleas easy. Irrespective of whether you’re growing them indoors or outdoors, this fertilizer powered with Biozome will help.

The fertilizer is designed to instantly turn the soil acidic. Also, to speed up the process, it feeds the plants at the drip line, which is the furthest edge of a brunch spread. This increases the nutrient intake of the Azalea plant by 100X.

With an NPK ratio of 4-4-4, you can ensure that your Azaleas will be getting enough nitrogen, potassium, among other nutrients. The fertilizer is also rich in sulphur, magnesium, and calcium. With the uptake of so many essential nutrients, you automatically reduce the risk of malnutrition and insect infestation.

The ingredients included in the fertilizer are feather meal, bone meal, poultry manure, potash, and sulfate. All these ingredients work together to provide the necessary nutrients. To accompany them, the fertilizer has bioactive ingredients like healthy bacteria, Mycorrhizal fungi, and Archaea. These are blended in an exact proportion, which is called the Biozome formula.

This is proprietary of Jobe’s, and many people have reported huge success with it. One user even compared two separate pots side by side and applied one with Jobe’s Biozome formula and the other with another fertilizer. She hailed the Jobe’s fertilizer superior for Azalea.

This fertilizer is USDA certified organic. This means there are no synthetic chemicals whatsoever. So if that’s your concern, you can get started with this fertilizer to enhance your Azalea’s growth.


  • Quick soil acidification
  • Supplements the further part of branch spread
  • Certified organic
  • Healthy bacteria and Mycorrhizal


  • The learning curve involved for proper dosing

5. Schultz SPF45170 All-Purpose Liquid Plant Food

This all-purpose liquid plant food is concentrated but mild in nature when used in correct proportion. And thus, it can be used for fertilizing a variety of plant species, including Azaleas.

For every quart of water, you’re only required to mix seven drops. Pour or spray on the soil evenly and witness the real growth in a few weeks. Being in liquid form, this fertilizer acts on the roots faster. It comes with a dropper that lets you easily measure the dosages. It’s important not to overdose the plant, which can later prove detrimental.

Such low requirements also mean that the product is going to last longer. So if you’re gardening on a large scale, this fertilizer will save you from shopping again and again.

With an NPK of 10-15-10, it delivers an ample amount of macronutrients to aid plant growth. If you’re growing fruits and vegetables within your house or in your garden, this plant food will fit your requirement.


  • Quick action
  • Delivers all essential micro-and macronutrients
  • All-purpose plant food, ideal for multiple plants
  • Easy to use


  • It might not be ideal for all Azalea species

6. Osmocote 274250 Smart-Release Plant Food Plus

This plant food from Osmocote delivers 11 of the 19 essential nutrients required for proper growth. This includes nitrogen, phosphorous, potassium, boron, chlorine, calcium, zinc, iron, among others.

Also, it feeds the roots up to 6 months from one application. This is thanks to its slow nutrient release characteristic that provides longevity. Just sprinkle a directed amount of granules (usually one scoopful per 4 square feet) around the plant and water from time to time. The granules will break down over time and provide all the 11 essential nutrients.

This ease of use is why Osmocote’s customers rave about this product and call it the best fertilizer for Azaleas.

Contrary to other products that claim lasting up to 6 months, this plant food actually lasts that long. This is because the outer layer of each granule comes coated with semi-permeable resin. This prevents the granules from breaking down all at once.

Because of the smart-release feature, this plant food from Osmocote is popular among indoor plant growers. They do not have to worry about fertilizing the plant often, and watering is more than enough to keep them in perfect health.

The Osmocote Plus has an NPK ratio of 15-9-12, which is ideal for Azalea’s growth. But it works equally well with other plant species.

If ease of use is what you’re after, then do consider this smart-release plant food seriously.


  • Provides 11 essential nutrients
  • Smart release feature delivers nutrients up to 6 months.
  • Suited for both indoor and outdoor gardens
  • Easy to use


  • Not suited for fast-acting fertilization requirements

7. Espoma HT36 Holly-Tone Plant Food Bag

Another Espoma product to make it to the list, this plant food bag is all you need to grow Azaleas easily.

Specifically created for acid-loving plants, it quickly turns the soil acidic. The compounds then act quickly on the drip line and allow the roots to intake nutrients in an efficient manner.

The plant food has a 4-3-4 NPK ratio. Out of the 4% Nitrogen, 2.5% is water-insoluble nitrogen. This means it doesn’t dissolve in water immediately. So it can keep on delivering nitrogen, among other nutrients, over a prolonged period of time.

Carrying the signature “Organic” label of Espoma, this plant food is made from bio matters. The Biotone blend of microbes like bacteria, fungi, archaea aid in the development process naturally. There are no harmful ingredients to affect the Azaleas or nearby plants.

Using the product is easy and straightforward. Just take the granules out of the box and spread them around the roots. Water regularly and watch your Azaleas develop into gorgeous shrubs. Irrespective of whether you’re growing shrubs, garden beds, or in containers, this food bag will help you become a better gardener.

Arguably, one of the best fertilizers for Azaleas.


  • Specifically for acid-loving Acazeas
  • 100% organic
  • Biotone formula which supplies essential microbes
  • Easy to use


  • Not ideal for fast-acting fertilization needs

Frequently Asked Questions (FAQs)

1. How do you revive old Azaleas?

Azaleas, when not taken proper care of, can turn dull and look in bad shape. But you, as a gardener, can always rejuvenate them back to their original vibrant condition.

The first thing experienced gardeners do prune them. In this process, you get rid of the live stems, branches, and other unnecessary parts. These consume the plant’s nutrients but do not add any value to it. You should always prune your Azalea plants from time to time. The best time to prone is after the flowers and leaves have fallen, i.e., after the spring.

Then get a soil test done to check if the growing conditions are suitable. Depending on the report, you can either munch the soil or apply fertilizers. This would make the soil acidic and support the plant’s growth.

2. Why are my Azaleas not blooming?

There are multiple reasons as to why your Azaleas might not be growing. The most obvious reason is pruning them incorrectly. The fresh buds for the next season come immediately within weeks.

You have to remove the buds in the early part of summer. But no later than that, otherwise, you’d then be without flowers for that season. If you’re pruned in mid-summer of any time later, then that’s why Azaleas are not blooming.

The next common reason why Azaleas might not be blooming is there’s too much nitrogen. So if you’ve applied fertilizers without getting the soil tested, then you have fed too much nitrogen. This can prevent Azaleas from blooming.

Other reasons might be they’re not receiving enough nutrients or water, the soil might be too alkaline. Or perhaps you’ve planted the wrong species of Azaleas.

3. Are eggshells good for Azaleas?

Eggshells are often a part of organic compost because they’re high in calcium. Calcium carbonate, which is also found in bones and teeth, is the main component. Like other plant species, Azaleas need calcium to be able to grow properly. So if your Azalea is calcium deficient, then yes, eggshells are good.

Especially in the early stage of Azalea’s development, eggshells will aid in cellular structure. Also, they’ll allow the roots to expand deeper and faster.

But, in general, eggshells are good for Azaleas and any other acid-loving plant. Crush the eggshells into powder form for proper breakdown.

It’s better to get a soil test done to check calcium deficiency.

4. Are coffee grounds good for Azaleas?

Coffee grounds are often discarded after use. But they’re great for growing Azaleas. The reason being their high acidic content because they’ve undergone brewing. Since Azaleas thrive in acidic soil, coffee grounds will create the perfect growing conditions for them.

If the soil is already high in nitrogen, then acidification of soil will be a major boost for Azaleas. They will be better able to derive nitrogen from the soil.

Instead of directly applying the coffee grounds to the soil, you can make them part of a mulch. This will offer the desired balance. The recommended volume is 25% of the compost.

5. How do you make Azaleas thicker?

When you say you want to thicken Azaleas, do you mean the flowers or the trunk?

For thickening the trunk, it’s simple. You’d have to provide a sufficient amount of compost, foliage, or the best fertilizer for Azalea around the sticks/trunks. Prune off the branches leaving the only sticks you want to thicken. This would allow the concentration of nutrients for a single stick and help it thicken compared to others.

Azaleas are acid-loving plants. So you shouldn’t plant anything that is acid-loving. Otherwise, it’d reduce the acidic content over time. So essentially, you shouldn’t plant blueberries or strawberries next to the Azaleas or closely enough.

Another way to look at this is the color combination. Do your Azaleas grow bright pink? Then plants like mountain laurel and Japanese andromeda will provide the best textural contrast.

Ferns also go down well with Azaleas. Hostas provide great diversity too.

You shouldn’t limit your creativity here and check what goes well with the Azaleas.

Finally, do take proper care of spacing. Azalea branches spread out and hence would need room to grow properly. Plant at least 4-6 apart from one another.

6. Why are the leaves on my Azaleas turning yellow?

Azalea leaves can turn yellow naturally when they’re about to drop off. So you shouldn’t freak out at first sight. Check if the leaves have aged and if it’s natural for them to turn yellow.

If not, then chances are the leaves aren’t receiving the proper nutrients. They might be suffering from chlorosis, which is common among plants when the soil becomes alkaline. As you know, alkaline soil is an Azalea killer. Thus you need to use quick-acting fertilizer to turn the soil acidic.

Yellow leaves also hint at possible iron deficiency. So it’s advised to prepare a compost or use fertilizer rich in iron. Once applied, the leaves should turn green over time.

Damaged or compacted roots are other possible reasons. So check for the reason and act accordingly.

To sum up

Azaleas are not only pleasing to look at but also fun to grow. Whenever you face any problem as a grower, go back to the basics. Are the plants appropriate to the environment? Does it requires sunlight or grows best under shade? Is the pH content of the soil adequate? Is watering being done at regular intervals? Answering these basic questions will make your life easier.

When it comes to fertilizing the soil, it isn’t a must but becomes crucial at some stages. As a requirement, you should get a soil test done to check for the pH level. Ideally, you should have a pH above 7, which confirms the soil is alkaline. Choose the best fertilizers for Azaleas to make the soil acidic enough for it to grow properly. You’ll surely find the appropriate one from the abovementioned options.

But special requirements exist, nevertheless. At the end of the day, it your call on what you want to apply, when, and in what proportion. That’s what differentiates seasoned gardeners from mediocre ones.