When To Fertilize Azaleas: Tips for Best Results

Jessica Stone
by Jessica Stone

Azaleas are arguably among the south’s most favorite flowering plants. Despite their reputation as being rather finicky, these stunning shrubs are simple to grow when you understand their basic requirements.

You should fertilize your azaleas in early spring and provide a second fertilization 12 to 16 weeks later. By doing this, your azaleas will have the necessary nutrients to last the year. Deposit fertilizer in under the bushes, 6 inches away from the branches’ tips. Finish by watering normally. Do not fertilize your azaleas during a drought.

Azaleas are a popular choice because of their low-maintenance and beauty. To ensure vibrant blooms and steady growth, some care is required. Armed with all the essential knowledge, you’ll be able to successfully grow gorgeous azaleas of your own.

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What Are Azaleas?

Azaleas are most known to be the iconic flowering shrubs of the South, but have the potential to thrive in many other parts of the country. They are a member of the Rhododendron family and the biggest difference between them and the Rhododendron plant is that Azaleas are considered to be deciduous bush, meaning they shed their leaves in the fall.

The flowers produced from azalea bushes are bell, funnel or tubular-shaped and most often very fragrant. These fragrant blooms can display a variety of colors in the Spring including bright orange, red, gold, lavender and other shades of purple.

While the majority of azaleas only bloom once a year, the Encore series is a variety that blooms more than once. With this type of azalea, it may bloom again in the summer and in the fall.

What Is The Best Way To Fertilize Azaleas?

Because of their shallow root system, azaleas can be especially prone to nutrient deficiency. Most often all they require is basic mulching and organic compost to achieve the right level of nutrients.

Simply incorporating compost or chopped up leaves into a well-drained soil can be all your azaleas need to flourish. However, once the plant starts to show signs of a severe lack of nutrients, you should start implementing a fertilizing schedule.

In fact, if you use wood chips or sawdust as much, you’ll likely need to fertilize, as these products remove nitrogen from the soil.

When Should You Fertilize Azaleas?

Established azaleas can be fertilized in the early spring and again about 12 to 16 weeks after. Deposit the fertilizer in the area under your bushes, about 6 inches past the tips of the branches. Afterward, water the entire area as normal.

Follow the instructions carefully and be especially conscious that their shallow roots make them vulnerable to overfertilizing.

Most all-purpose fertilizers found at your local hardware store will not provide all the essential nutrients that azaleas require. You’ll need to purchase one that is specifically designed for use with azaleas.

These fertilizers will contain a special blend of nutrients that includes sulfur, to keep the soil pH at the optimal zone, and iron, calcium and magnesium, to prevent nutrient deficiencies.

How Do You Select The Correct Azalea Variety?

Fertilizer only works if you have the correct Azalea variety in your garden, and planted in optimal growing conditions.

With the assistance of modern plant breeders, azaleas can now by enjoyed in more than just the south and coastal areas. By simply selecting the right plants, gardeners all across the United States can enjoy the beauty and fragrance of this spectacular shrub.

When choosing the best azaleas for planting in your garden, consider the following:

  • Light conditions. Azaleas are generally considered shade plants, but some varieties exist that can withstand, or even require, direct sunlight. For example, in northern climates, where the sun is generally less powerful, azaleas favor more sun. Choose the correct azalea variety that fits with the light conditions in your garden to ensure abundant blooms.
  • Desired maturity size. Some types of azaleas, native included, can reach heights of up to 20 feet and higher. However, home gardeners can opt for smaller varieties. For examples, dwarf azaleas grow between two and three feet tall. Garden azaleas, on the other hand, stay around four and six feet high. Avoid selecting azaleas based on their size upon purchase and instead choose based on the height they reach at maturity.
  • Growing zone. Choosing a type of azalea that can endure your particular winter conditions is crucial to spring blooms. Sometimes, flower buds will begin to form long before winter even starts. A large majority of azaleas are only bud-hardy in the southern half of the country, while other northern types can survive in temperatures below 45 degrees Fahrenheit.
  • Flower form and color. Azaleas come in a wide variety of colors and shapes that include ruffled blooms or spider-like petals. They truly offer something for everyone. In order to know exactly what yours will look like, buy your azaleas when they’re in full bloom.
  • Bloom time. Azaleas are undoubtedly known for their springtime blooms, but they also can be found in early, mid or late flowering varieties. The reblooming types will flower in the spring and again in the fall. If you’d like to enjoy azalea blooms for a longer period of time, consider planting a mixture with staggered bloom times in your garden.
  • Leaf retention. While most azaleas are deciduous, some are “evergreen,” or keep their leaves throughout the year. Understand what you’re getting with the type that you choose so you can know what to expect. That way, you can respond appropriately when you notice leaves dropping.

What Soil Do You Use For Azaleas?

Azaleas are considered to be “acid-loving” plants and fall within the same plant family as blueberries. In order to reach their full potential for beauty and health, acid-lovers, like azaleas, need to be grown in an acidic soil with a pH between 4.0 and 5.5.

This range ensures that all the essential nutrients azaleas require are always readily available to them. When the pH increases, this can cause yellowing leaves resulting from a loss of nutrients.

Some areas of the United States already have naturally occurring acidic soil. However, soils with a higher pH may require some sort of amendment to help meet azalea requirements. It is not uncommon for azalea soil to need supplemental sulfur or ammonium sulfate. Perform a simple soil test to determine what the pH is so you can adapt it for your azaleas.

Additionally, azaleas require a soil that has good aeration and draining. This will maintain that the roots do not sit in water and get plenty of oxygen. Adding compost, or other organic matter, when planting can be beneficial to the soil. When it comes to planting, you want to avoid placing azaleas too deep in the soil. Plant them at a level that is just slightly higher than how they were originally growing in the nursery pot.

How Much Water Does Azaleas Need?

When compared to other shrubs, azaleas consist of a more shallow root system. Most of their roots will remain in the upper 4 to 6 inches of soil and are very vulnerable to water stress. For azaleas, you want to maintain a consistently moist soil that isn’t excessively wet and doesn’t dry out completely.

In general, azaleas planted in more sunny areas will require more water than those grown in the shade. Consider implementing a 3-inch layer of organic mulch to help prevent temperatures from shifting too much and preserve soil moisture.

How Do You Know If Your Azaleas Need Water?

You can check the soil around your azaleas by touch and only water when it feels dry. Water the soil at a slow rate, deeply and thoroughly so as to equal close to 1 inch of rain per week during summer months. If you’re anything like me, you’ve killed at least one plant from simply overwatering. With azaleas, overwatering can be detrimental, as a soggy soil can cause root disease.

For best results, water the soil surrounding the plant inside of just the leaves or implement drip irrigation. Water that remains on the leaves of plants generally results in fungal diseases. To prevent this, water your azaleas early in the day. That way, the sun has enough time to dry the leaves that do get wet.

Signs Of Azalea Nutrient Deficiency

In order to know if your azaleas require the use of fertilizer, you need to understand when they’re experiencing a lack of nutrients. Some of the signs include:

  • Leaves that are smaller than normal
  • Yellowing leaves
  • Leaves that have dropped early
  • Stunted growth
  • Dead branch tips
  • Branch tips that are darker green than normal

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Pruning Azaleas

Another essentially step in the overall health and abundant growth of azaleas is the pruning. While many varieties of azaleas can function well with little to no pruning, they can still tolerate some.

If you choose to prune your azaleas, timing is essential and pruning done at the wrong time can thwart blooms next season. To help prevent any loss of blooms, always prune your azaleas immediately after they’ve finished blooming. For the reblooming variety, prune these right after the first bloom period to enhance the number of flowers next year. Dead or damaged wood can be pruned at any time.

Jessica Stone
Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

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