The Ultimate Guide to Growing and Caring for Stewartstonian Azalea

Stewartstonian Azalea

Stewartstonian is an evergreen plant and a member of the Gable hybrid group. It is a medium-sized plant measuring 4-5 feet low-spreading shrub. It is best known for its distinctive deep-green shiny leaves that often turn to a chocolate-reddish color by fall, especially in regions with very cold winters. The older leaves are also shed during winter, with newer mahogany-colored leaves growing in their place. During spring, a beautiful cluster of bright orange-red flowers blossoms, attracting pollinators to your garden. Compared to most rhododendrons and azalea plants, the Stewartstonian is a four-season shrub best planted in the fall and spring. This post will discuss growing and caring for your Stewartstonian Azalea plant.

What is a Stewartstonian Azalea

According to Garden Analyst, Stewartstonian Azalea is among the hybrid made by Joseph Gables, a professional farmer and well-knowledgeable nurseryman, who resided in Stewartstown Pennsylvania. Hence, this plant’s botanical name is Rhododendron x Gable Stewartstonian. Joseph created the gorgeous Stewartstonian cultivar by crossing different Azaleas species. The Azalea cultivar belongs to the Rhododendron genus of 500-900 species, but human selection has resulted in a significant increase in hybrid plants.

This plant is native to several continents, including North America, Asia, and Europe. Stewartstonian cultivar is a slow-growing shrub that can take a few years to mature, but once fully grown, it can last for more than forty years. With its dense growing nature, this plant can grow to heights of 3-5 feet and four feet wide. The Stewartstonian plant is an evergreen shrub that is distinctively spotted by its glossy, dark green leaves and abundant clusters of orange-red or vivid dark orange flowers.

How to Grow Stewartstonian Azalea

The Stewartstonian plant requires a moderate amount of maintenance. You can start by placing them in a partial shade and grow them in properly drained soil. Like all members of the Azalea family, it is often advisable to keep them well-pruned, irrigated, and fertilized. According to The Spruce, below are some simple guidelines on how to grow your Stewartstonian Azalea plant:

Finding a suitable location

To ensure your Stewartstonian plant remains healthy, it is important to grow it in the right location. This means growing it in a spot where it is protected from the harmful afternoon heat and strong winds. This plant should also be grown in a location free from pecans, butternuts, walnuts, and hickories that can damage them.


The Stewartstonian cultivar grows best in partial shade. It should be protected from direct sun rays, though it can withstand a fair amount of sunshine and cool climate conditions during cold months.


The Stewartstonian Azalea plant requires organic mulch, which should be between 2-3 inches thick, and is comprised of pine needles, wood chips, and bark. This will not only retain your plant’s moisture but also keep the soil temperature stabilized and prevent the growth of weeds. Applying this plant in the spring with a highly acidic fertilizer is often recommended, or applying compost manually if you want to lower the soil pH further.


This Azalea cultivar usually prefers well-drained and slightly acidic soil. The pH value of the soil should range from 5.0-5.5, which can be easily achieved by adding iron sulfate or sulfur to the soil. You can improve the soil’s drainage by mixing it with large amounts of decomposed organic matter. The Stewartstonian plant is very sensitive to the soil pH and can easily die if grown in less acidic soil or soils contaminated with toxins from trees in the walnut family.

Temperature and Humidity

The Stewartstonian Azalea plant hybrid can withstand very cold temperatures but grows best in temperatures that range between 55.4 to 64.4 degrees Fahrenheit. They also do not prefer growing in areas subjected to prolonged high temperatures of 90 degrees Fahrenheit and cannot survive in areas with temperatures below -5 degrees. This cultivar also does not prefer to grow in areas with hot, dry, and dense air; such conditions can lead to leaves falling. If grown in drier climates, you should increase the watering rate, especially during winter.


It is often recommended that you trim your Azalea plant after the orange-red flowers blossom fades to help keep it in an attractive and manageable size. Minimal pruning will work best in allowing your plant to maintain its naturally graceful form. It should be noted that pruning should only be done once the blooming period ends; this gives your plant adequate time to grow the next spring’s gorgeous flowers.


The Stewartstonian plant grows best in areas with plenty of moisture, so you must frequently water it to keep the roots slightly wet. Ensure the roots do not become waterlogged and do not dry out completely. While this plant is drought-resistant and can go several weeks without watering, regular watering and sprinkling water on the leaves will help your plant look attractive and healthy. You must also keep the soil for this plant moist throughout the growing period and apply mulch to help retain the soil moisture.

How to Care for your Stewartstonian Azalea

According to Plant Addicts, the Stewartstonian Azalea cultivar belongs to the Rhododendron genus. As a result, this plant requires the same care as the Azaleas and Rhododendron species. It is an easy-to-maintain plant and cannot survive in areas with temperatures below 25 degrees Fahrenheit, especially if the plant is young and the drop in temperature is sudden. Prolonged exposure to the sun and icy winds can damage your evergreen Azalea plant.

If your plant shows any signs of winter damage, you will be required to provide it with some protection. To protect the plant, dig stakes in the ground and curtain with a porous material, such as old bed sheets. Ensure the cover does not touch the foliage and avoid covering the plant with any plastic material. This is because plastic materials can trap excessive moisture that can damage and freeze the plant. It is also advisable to be very careful when selecting Azalea varieties based on your climate and zone, which plays a vital role in determining whether your plant will survive.

Propagating Stewartstonian Azalea

You can use various methods to propagate your Stewartstonian Azalea plant, such as; layering, seeds, grafting, and stem cuttings. Propagation through stem cutting is often considered the easiest way, and it ensures your new plant will look like their parent. When propagating your Azalea cultivar from cuttings, it would be best to use semi-wooden cuttings, where new shoots are growing.

You can cut all the leaves, except those on the top of the stem cutting. Dip the bottom of the cutting into a powdered acidic fertilizer and place it into the pot with moist, well-drained soil. Make sure the stem cuttings are kept in a warm place and away from exposure to direct sunlight. If you follow these guidelines properly, your Stewartstonian root system should develop within the first eight weeks, when you can then transplant these new seedlings into a permanent growing spot, such as your yard.

Stewartstonian Azalea Spacing

The Stewartstonian Azalea is an upright, spreading Azalea cultivar with woody stems. This plant can grow to heights of 5-6 feet tall and 4-5 feet wide. As a result, Stewartstonian plants should be grown about two to three feet apart to allow more space and create a hedge. This Azalea plant is mostly preferred for its vivid dark orange or orange-red flowers that will gorgeously brighten any dull garden, abundantly blooming in spots of partial shade.

This perfect all-season decorating plant will provide your yard with rich, green foliage. Although these shrubs are usually low-maintenance during summer, you are advised to consider possible winter care methods for your Azalea cultivar. Caring for your Stewartstonian plant in winter is usually straightforward if you plan early enough and take the necessary precautions.

Winter Preparation for Stewartstonian Azalea plant

Providing your plants with the needed care during winter will help ensure they remain healthy and strong even when the temperatures are extremely low. As mentioned earlier, all Azalea cultivars, including the Stewartstonian plant, are picky about soil. The roots are usually very delicate and can be easily damaged by contaminated soil. According to My Perfect Plants, soil with excellent drainage is another essential factor when preparing the soil before planting.

The soil must be of good quality, acidic and loamy topsoil, with a pH range of 4 and 6. As you prepare for winter, you are advised to slow down and eventually stop irrigating your plants. During autumn, reduce the watering rate to one-third to allow the plant to toughen for winter. It would be best to soak the plant’s root during the winter months as it usually becomes dormant. This will also protect your Azalea cultivar from drying out when moisture is lost through the leaves.

Choosing the right container for Stewartstonian Azalea

Many Azalea cultivars, whether evergreen or deciduous, can grow to four and six feet in height and width. The dwarf varieties normally reach a mature height of two to three feet. That said, it is important to consider the mature dimensions of your Stewartstonian plant when selecting the right container to plant them.

Since the roots need adequate room to stretch and grow, you must choose a container at least two feet wide and deep with enough drainage holes in the base. You should also ensure the container is large and heavy enough so that your pants do not fall over in strong winds. Any concrete, wooden or plastic container can work perfectly as long it has adequate drainage holes in the base and a wider bottom. A large terra cotta container can work fine but is very heavy to move.

Landscape Uses for Stewartstonian Azaleas plant

The Azalea cultivar is among the most popular spring flowers in North American landscaping and is often grown in areas with favorable growing conditions. The Stewartstonian plant is best known for its beautiful evergreen foliage and distinctive orange-red blossoms, making it the perfect choice for any all-season. This attractive plant works well in decorating woodland gardens or as a hedge for your home.

What are the common pests and diseases that affect the Stewartstonian Azalea plant?

According to ProFlowers, the most common disease affecting the Stewartstonian cultivar are fungal infections that attack roots, leaves, flowers, and wooden parts of the plant. Fungal infections on the roots and upper parts of the plant usually lead to the formation of dark, recessed areas on the wooden branches. Another sign of fungal infection is white cotton-like growths on the leaves, brown rotten buds, and discolored flowers. If the plant’s roots are waterlogged, the crown and root can be easily attacked by a fungal disease that can damage the plant. This Azalea cultivar is often attacked by common pests such as; caterpillars, mites, nematodes, mealy bugs, whitefly, scale, leafhoppers, stalk borers, and lace bugs.

How to manage common pests and diseases

Stewartstonian plants, especially ones grown outdoors, are susceptible to pests and diseases. Crown or root rot caused by overwatering can be easily controlled by regulating the rate at which you water your plants. Make sure the soil is well-drained to avoid overwatering the plant and the soil becoming too moist. If the leaves turn yellow, it may be a sign of iron deficiency that often occurs when the soil pH is too high. This can be corrected by applying an acidic fertilizer or mulching with an acidic organic substance, such as pine needles or peat moss.

You get rid of the infected wooden branches by snipping off the infected ones to avoid them from contaminating the other healthy branches. Watch out for female azalea lace bugs that suck sap from the plant’s leaves and lay their eggs inside the leaf tissue. This gives the leaf a brown, spotted appearance. If you notice any damage to the plant’s leaves, cut off all the affected ones. Another effective method of managing pests and diseases is using fungicidal powders and sprays that may help prevent or even cure some fungal infections. Regular pruning is also recommended to help improve air circulation in the plant.

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