How to Grow Azalea

A blooming azalea shrub is one of the nicest sights of spring. Sometimes called the Royalty of the Garden these plants come in a range of colors and sizes. Consequently the azalea is considered a great way to add early season interest to an outdoor space.

Newcomers to growing azalea plants will be pleased to learn that they are also pleasingly easy to grow. Despite their showy appearance the plants are also pleasingly versatile, meaning that they are suitable for a range of growing conditions.

For many the azaleas colorful blooms are a sure sign that spring is underway. A pleasingly easy to grow plant, adding a few azalea plants to your garden is a great way to bring early season interest. 

Warning the azalea is toxic, if consumed, to both animals and humans. If you have sensitive skin wear gloves and a long sleeved shirt when handling the plant.

Azalea Varieties

There are thousands of different azalea varieties for you to choose from.

Deciduous varieties are the hardiest types of azalea. Most deciduous types happily grow in USDA Zones 4 and higher. Some varieties, such as the bright pink roseshell, are hardy to USDA Zone 3.

Evergreen varieties are suitable for USDA Zones 6 and warmer. You can grow evergreens in cooler zones, just remember to provide winter protection.

If you want to add height and structure to your garden try growing tall varieties. For example the Sweet Azalea is a white flowering plant that can reach up to 20 ft in height.

Conversely low growing varieties such as the bright red flowering Joseph Hill are ideal for providing ground cover. Another good ground cover option is the early summer flowering Flame Creeper. As the name suggests this variety produces bright orange, flame like flowers.

In addition to low growing varieties there are also weeping cultivars. These, such as Pink Cascade, look particularly effective if allowed to spill over the edges of containers or raised beds, creating a pleasing waterfall effect.

Low growing cultivars are a great way to bring colorful groundcover to the garden. 

Most azalea plants flower in the spring. If you want to extend your flowering season try planting a mix of early flowering, mid season and late flowering varieties.

Red ruffles is a pleasing early flowering hybrid. Both Coral Bells, with its pink flowering habit, and Sherwood Red are reliable, early to mid season flowering varieties.
A pleasing light flowering variety is Weston’s Lemon Drop. This produces soft yellow flowers during June and July.

George Lindley Taber is a reliable mid season flower producing pink and white blooms. Finally, Sweet September is another pink flowering variety. As the name suggests Sweet September flowers in September, bringing late season color to the garden.

How to Plant

Planting your azalea correctly helps the plant to grow strong and flourish. It also helps  the plants to stay healthy and problem free.

Where to Position

Positioning an azalea correctly helps the plant to flourish and stay disease free.

Azalea plants do best in cool or lightly shaded positions. Avoid planting in full sun. This can cause the foliage to burn. Azalea plants struggle in temperatures over 85 ℉.

A single azalea planted on its own, as a statement plant, can be a standout feature. However mass planting a group of azaleas, as part of a woodland or forest scheme, can create an eye-catching burst of color. Azalea flowers cover the entire plant, meaning that the shrub also looks good in front of evergreens such as conifers or pines.

When choosing your position, try to find somewhere close to other acid loving plants, such as hydrangea, daffodils or camellias. This form of companion planting helps your azalea to thrive.

These plants do best in acidic soils. To maximize flowering try planting in light shade. Overly bright or full sun positions can cause the foliage to burn.

What Soil do Azalea Plants Prefer?

Azalea plants do best in humus rich, well-draining soil.

The soil should be slightly acidic. These are ericaceous, or acid loving, plants. A pH profile of between 4.5 and 6 is ideal. A soil test kit will tell you the condition of your soil, allowing you to provide the perfect growing conditions. There are a number of ways to make alkaline or neutral soil more acidic.

If your soil is heavy or poor-draining, try planting in containers or raised beds.

Before planting work over the soil. Working in compost helps to enrich the soil as well as improving drainage.

When to Plant

Plant in the spring,  after the last frost has passed.

Harden plants off before planting.

Dig the soil over before planting, removing any weeds and pebbles. If you haven’t already done so, work in some aged compost or organic material. This enriches the soil, giving your plants a helpful nutrient boost.

When you are ready to plant, dig a hole with a good shovel in the soil. This hole should be large enough to comfortably hold the plant’s root system. If you are unsure, place the container in the hole. If the container fits comfortably in the hole, it is large enough.

Gently remove the plant from the container. If the plant is difficult to remove, squeeze the sides of the container. This loosens the soil helping you to slide out the plant without damaging the roots or causing the plant too much trauma.

Center the plant in the hole. The top of the root system should be level with the soil. When you are happy with the position of the plant, fill in the hole.

Gently firm the soil down. Don’t compact the soil. This can hamper drainage and cause the plant’s root system to rot.

After planting apply a thin layer of mulch. Organic mulches such as pine straw, oak leaf mold or composted bark are ideal. Mulching around a plant helps to keep the soil cool and retain moisture. Mulching regularly also helps to discourage weed growth.

Adding an additional layer of organic matter, after the mulch, helps to provide the plants with a slow supply of nutrients throughout the growing season. This means that you won’t need to fertilize the plants.

Planting in Containers

The compact growth habit of the azalea makes it ideal for container gardens. Planting in self watering containers cuts down on the amount of time you need to spend watering plants. This is ideal for busy people who love their plants.

Your container should be large enough that the plant has lots of room to spread its roots. Planting in a small container can stunt growth. The container should also have drainage holes in the bottom. Azalea plants rot if allowed to sit in wet soil.

Planting in containers is similar to planting in the ground or a raised bed.

Fill the container in fresh, well-draining or general purpose compost or potting soil. Make a hole in the center of the container and position your plant. The top of the root system should be level or just below the level of the soil. Planting too deeply can cause the crown of the plant to rot.

Firm the soil down around the plant. Water well, until water seeps out of the drainage holes. Cover the soil with a thin layer of organic mulch.

Position the container in a light position, which receives some afternoon shade. Partial or dappled sunlight positions are also great. Avoid direct sunlight or total shade positions.

Azaleas do well in containers. Just remember to provide some winter protection.

Most varieties are considered hardy in USDA zones 5 to 9. However container plants are often more exposed than those planted directly into the soil. This means that you need to provide some form of winter protection. Horticultural blankets or fleeces such as the Gardaner Plant Cover offer protection from both winter frosts and pests. Alternatively, move the containers inside during the fall and winter months.

How to Care for Azalea Plants

Once planted, care is pleasingly straightforward.

How Often to Water

Water azalea when the soil around the plant is dry to the touch. Devices such as the Gouevn Soil Moisture Meter provide an accurate way to measure the moisture levels in your soil.

Remember plants growing in containers dry out more quickly than those in the soil.

If you are concerned about your water usage, try harvesting your own rainwater. This is an easy process that helps to keep your plants hydrated without wasting natural resources. Watering with rainwater is also preferable to tap water because it is usually less alkaline.

Azalea plants have a shallow root system so they do best in moist soil. Mulching the soil helps to keep the roots hydrated.

When to Fertilize

If planted in rich soil and amended with an organic mulch every year there is no need to fertilize an azalea.

If your soil is poor apply a fertilizer designed for acid loving plants once a month during spring and summer. Alternatively, you can apply a slow-release fertilizer a few times during the growing season.

There is no need to fertilize during the fall or winter months.

Pruning

Deadhead regularly during the flowering season. This helps to keep the appearance of the plants neat. It also encourages more flowers to form.

If the plant looks straggly, once flowering has finished prune well with a sharp pair of garden scissors. If the appearance of the plant seems fine, confine pruning to no more than a light trim. This helps the plant to keep its shape and size.

Pruning is best done after flowering has finished. Don’t prune in the early spring. This reduces the flowering habit of the plant.

Companion Plants

Companion planting is the process of planting mutually beneficial or similar plants together. This can create pleasing planting schemes as well as making plant care easier.

The azalea is closely related to the rhododendron plant. This means that the plants work well together. Pieris japonica or Japanese andromeda and Mountain Laurel (Kalmia Latifolia) are two medium sized evergreen shrubs which provide floral interest and textural contrast to azalea plants.

Other companion plants, which add color in the fall and inter include Barberry, Witchhazel and Summersweet.

Perennial bulbs such as daffodils, snowdrops and hellebores also work well alongside azalea plants as do hostas. In fact the hosta is a great way to add contrast and interest when planted alongside an azalea. Similarly, incorporating ferns into a planting scheme helps to add textural interest and color.

How to Propagate

Azalea plants are easily propagated from cuttings. This is a great method if you want the new plants to resemble the parent plant.

To propagate take semi-hardened cuttings. These are parts of the plant that are slightly harder than soft new growth but are not yet completely brittle. This means that they don’t bend easily. Only ever take cuttings from healthy parts of a plant.

Root cuttings in clean containers that have drainage holes in the bottom. Fill the containers with well-draining fresh rooting compost. Alternatively you can fill the containers with an equal mix of perlite and peat.

Wet the soil.

Trim the cutting to a point just below a leaf attachment. Remove the leaves from the bottom third of the cutting. You should also remove all the flower buds.

Dip the end of the stem in rooting hormone. This helps to encourage root formation but is not necessary.

Plant the cutting so that the lower third is in the soil. Water gently.

Place your cuttings in a propagator. The EarlyGrow Propagator comes with a height extender, meaning that it can be extended to protect sensitive seedlings as they grow. Alternatively cut a clean, empty drink bottle in half. Place the top half over the cutting. This creates an effective propagator while also reusing old plastic bottles. Placing seeds in even a makeshift propagator helps you to maintain temperature levels as well as helping the soil to retain moisture.

Place the cuttings in a bright, indirect light position. Check regularly, watering the soil when it dries out. If successfully, roots will form within two months.

To check that roots are present gently tug the plant, feeling for resistance. Once you feel resistance remove the covering from the cuttings. You can now begin exposing the plants to more light. Increase gradually, exposing plants to a few more hours of light every day. As the plants grow continue to protect them until the following spring. They should then be large enough to plant out.

Common Pests and Problems

If planted in a favorable location azalea plants are largely pest and problem free.

Azalea Bark Scale is common in eastern parts of the United States. This can cause a sooty mold, or white cottony masses to cover the plants. Cut away and destroy affected parts. Affected plants can also be treated with horticultural oil.

Azalea caterpillars can quickly defoliate a plant. Regularly check your plants for signs of infestation. While chemical products are available, these destructive pests can be easily removed simply picking them off the plant.

Lace bugs are another common pest, causing foliage to turn pale or yellow. Upon inspection you will notice that the underside of affected foliage is covered in small, black bugs. Apply insecticidal soap to affected plants to remove infestations.

Regularly check your plants for signs of problems such as disease or infestation. Noticing potential problems quickly gives you a good chance of solving them before they can cause too much damage. 

Whitefly can also cause foliage to yellow. Applying neem oil to the foliage helps to control infections.

Stunt nematodes attack the root system of a plant, causing growth to become stunted and foliage to yellow. While there is no way to control nematode infestations, adopting good growing and watering practices reduce the chances of nematode striking.

Leafminers tunnel through foliage causing it to blister or curl up. Cut away and destroy affected parts of the plant.

Diseases such as gall, causing foliage to curl and fade, twig blight and rust can be devastating if allowed to spread. Cut away affected parts of the plant and destroy.

Peat blight, a fungus which causes pale, watery spots to form can be treated by the application of a fungicide. Similarly powdery mildew, causing white, powdery growth to form, can also be treated with a fungicide spray. Organic fungicides such as Bonide’s Sulfur Plant Fungicide can also be used.

Bright and colorful, the azalea is a reliable way to bring color to the garden. With a little extra care the plants can be encouraged to flower abundantly during the spring months. 

Easy to grow and pleasingly low maintenance the azalea is a great way to introduce spring color to your garden. Many deciduous types also add color and interest in the fall. Meanwhile evergreen varieties bring greenery to your garden all year round. A neat and compact growth habit means that the azalea is also a great option for container gardens.