Swamp Azalea (Rhododendron viscosum)

Also known as: Swamp Honeysuckle, Azalea Viscosa

Rhododendron viscosum, commonly called Swamp Azalea, is a deciduous shrub from the eastern United States that draws in hummingbirds and butterflies. Typically reaching heights of up to 2.5 meters, it thrives in woodland gardens, rain gardens, and shrub borders, favoring partial shade.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Swamp Azalea

Lifespan

Perennial

Plant Type

Shrub

Plant Height

61 cm to 2.5 m

Spread

90 cm to 2.5 m

Leaf Color

Green

Flower Size

1 to 2 inches (2.5 to 5 cm)

Flower Color

White Pink

Images of Swamp Azalea

Quickly Identify Swamp Azalea

Fragrant white to pale pink tubular flowers in late spring to early summer.

Dark green oblong leaves, 2 to 6 inches (5 to 15 cm) in length.

Smooth, glossy elongated fruit capsule, splitting to disperse small seeds.

Shrub reaching 5 to 6 feet (1.5 to 1.8 meters) in height and width.

Leaves with lustrous green color, oval to oblong, networked venation, slightly paler underside.

Scientific Classification of Swamp Azalea

Phylum

Vascular plants

Class

Dicotyledons

Order

Ericales

Family

Heath

Genus

Azaleas

Species

Swamp Azalea

Planting and Growing of Swamp Azalea

Care Difficulty

Easy

Watering Schedule

Every 4 days

Sunlight Requirements

Partial sun

Sunshine Duration

4-8 hours

Ideal Temperature

65-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

4.5-6

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Swamp Azalea?

Rhododendron viscosum, also known as the swamp azalea, enjoys a consistent moisture level. Watering should aim to moisten the soil deeply but not to the point of waterlogging. Each time you water, do so until the water reaches the root zone, providing about 500 milliliters. This ensures that the water penetrates the entire root ball, avoiding both shallow watering and root rot.

What are the symptoms of an underwatered Swamp Azalea? ›

What should I do if my Swamp Azalea is not getting enough water? ›

What are the symptoms of an overwatered Swamp Azalea? ›

How to save an overwatered Swamp Azalea? ›

What Are the Sunlight Requirements for Swamp Azalea?

Sunlight Requirements: Partial sun, Full shade

Duration of light: 4 to 6 hours

Rhododendron viscosum prefers partial sun to full shade conditions, thriving with 4 to 6 hours of daylight. Ideal lighting ensures optimal photosynthesis, resulting in vigorous growth, lush foliage, and abundant flowers.

What is the best sunlight condition for Rhododendron viscosum? ›

How can one achieve this ideal sunlight condition? ›

What are the benefits of ideal lighting for this plant? ›

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What Is the Ideal Temperature Range for Swamp Azalea?

Ideal Temperature: 65 ~ 75℉

Rhododendron viscosum thrives in temperatures ranging from 65°F to 75°F. This range is optimal because it mirrors the temperate climates where this species naturally occurs, providing a warm yet moderate environment conducive to healthy growth and blooming.

What Soil is Best for Swamp Azalea?

Soil type: Loam, Acidic soil, Peat soil, Sandy loam

Soil PH: 4.5 ~ 6

Rhododendron viscosum thrives in soil that effectively retains moisture without becoming waterlogged. Good moisture retention ensures the plant's roots remain hydrated, promoting healthy growth and vibrant blooms. This species benefits from a nutrient-rich soil environment. A soil high in organic matter provides essential nutrients that support its vibrant foliage and abundant flowering. While moisture retention is crucial, Rhododendron viscosum requires soil with excellent drainage to prevent root rot. Proper drainage ensures that excess water is removed, protecting the plant's root system. More About Soil→

How to Fertilize Swamp Azalea?

Fertilizer type: Balanced

For Rhododendron viscosum, use a balanced fertilizer at half strength. Typically, 1/2 cup of granules per plant is sufficient, ensuring not to exceed the recommended amounts on the package. This plant is sensitive to over-fertilization, so caution is key. More About Fertilizing Techniques→

How to Prune Swamp Azalea?

Pruning Time: Spring, Summer, Autumn

Always use clean, sharp pruning shears to prevent the spread of diseases. Wipe down your tools with rubbing alcohol before and after use. This ensures that you’re not transferring any pathogens from one plant to another. Begin by removing any dead, diseased, or damaged wood. Cut these branches back to a healthy part of the plant or to the ground. This will enhance air circulation within the plant and contribute to overall plant health. Selective thinning involves cutting some of the branches back to the main stem or to a lateral branch to reduce density. This will help improve air circulation and light penetration, promoting better flower and foliage development. More About Pruning Techniques→

How to Propagate Swamp Azalea plant?

Propagate Time: Spring, Early summer

Collect ripe seeds from mature plants and clean them thoroughly by removing any pulp or debris. Soak the seeds in water overnight to encourage faster germination, and plant them in well-drained soil with a light covering of soil on top.

Select healthy, young stems from the plant. Cut 4-6 inch sections just below a node, remove the lower leaves, and apply rooting hormone to the cut ends. Plant them in a suitable rooting medium, ensuring that at least two nodes are buried.

Choose a low-hanging branch and bend it towards the ground. Bury a section of the stem under the soil, ensuring at least one node is covered, and secure it with a u-shaped pin. Wait for roots to develop at the buried node before severing it from the parent plant.

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How to Repot Swamp Azalea plant?

Repotting frequency: Every two years

Repotting should be done when the roots start circling the pot, indicating it's root-bound. This usually happens every couple of years. Other signs include reduced growth and water drainage issues. It's best to repot in spring or autumn when conditions are favorable for root recovery and growth.

Select a pot that is one size larger than the current one. Ensure it has drainage holes to prevent waterlogging, which can lead to root rot. A slightly larger pot will give roots room to grow without overwhelming them with too much new soil, which can retain excess moisture.

Rhododendron viscosum prefers acidic, well-drained soil. Use a mix specifically designed for azaleas or rhododendrons. This type of soil will provide the necessary aeration and avoid compacting, which allows roots to penetrate and access nutrients effectively.

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Toxicity of Swamp Azalea

Is Swamp Azalea toxic to humans?

Swamp Azalea belongs to the *Rhododendron* genus, which is characterized by the presence of varying concentrations of Grayanotoxin, a potent toxin found in all its tissues. Individuals who come into physical contact with the plant may experience rashes, particularly those who are sensitive. The pollen from this plant can provoke irritation in mucous membranes, and ingestion may lead to symptoms including nausea, vomiting, arrhythmia, hypotension, and even hallucinations in humans. Among the different varieties, Swamp Azalea is identified as one of the most toxic, and it is crucial to ensure that children are kept away from it at all times. Grayanotoxin's potency is such that honey derived from *Rhododendron* pollen may also pose harmful effects due to its potency.

Is Swamp Azalea toxic to cat?

Swamp Azalea is known to be toxic to felines. If a cat consumes any portion of this plant, it might encounter various health issues since every part of the swamp Azalea is harmful. There is a considerable risk if a cat unintentionally eats parts of this plant. Cats that are affected may exhibit signs of discomfort, illness, or pain. In light of the lack of detailed information regarding the specific toxic compounds in the plant, it is crucial to monitor for visible signs of distress in cats. If ingestion is suspected, cat owners should promptly seek veterinary assistance to manage the potential toxicity.

Is Swamp Azalea toxic to dog?

Swamp Azalea is recognized as a poisonous species for dogs. If a dog accidentally ingests any part of the swamp Azalea, it faces a considerable risk of toxicity. Every part of the plant, including its leaves, flowers, and stems, harbors toxic compounds that can provoke negative health reactions in dogs. Signs of poisoning may manifest as gastrointestinal disturbances, lethargy, irregular heart rhythms, hypotension (reduced blood pressure), and in critical situations, it could escalate to coma or death. It is essential for dog owners to vigilantly oversee their pets and restrict access to swamp Azalea. Should there be any suspicion that a dog has consumed any portion of swamp Azalea, prompt veterinary assistance is vital for achieving the most favorable outcome.

WARNING

The judgment on toxicity and danger is for reference only. We DO NOT GUARANTEE any accuracy of such judgment. Therefore, you SHALL NOT rely on such judgment. It is IMPORTANT TO SEEK PROFESSIONAL ADVICE in advance when necessary.

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