Rhododendron Rhododendron 'Saint Merryn'

☠ Toxic to humans
🐾 Toxic to pets
🌸 Blooming
🍪 Not edible
‍🌱 Hard-care
rhododendron 'Saint Merryn'


The Rhododendron 'Saint Merryn' is characterized by its striking flowers and lush foliage. The flowers are a notable feature, presenting a vibrant array of colors. Most commonly, blooms may exhibit a deep pink hue with subtle variations that include lighter shades, possibly with patterned speckles or a fading gradient towards the petal's edges, creating a visually striking contrast. These blossoms group together in large, rounded clusters known as trusses, making the floral display particularly eye-catching during the blooming season. The leaves of 'Saint Merryn' contribute greatly to its aesthetic, with a glossy, evergreen quality that provides year-round visual interest. The foliage is typically rich green, and the leaves are leathery to the touch, with a smooth surface and a pronounced central vein. They are oblong in shape, often with a slight tapering at the tip. Together, the bold flowers and robust foliage create a lush, dense appearance that can make the Rhododendron 'Saint Merryn' the centerpiece of a garden display. Its flower clusters provide a dramatic pop of color against the backdrop of its verdant leaves, making it a popular choice for ornamental plantings.

Plant Info
Common Problems

About this plant

  • memoNames

    • Synonyms

      Saint Merryn Rhododendron

    • Common names

      Rhododendron 'Saint Merryn'.

  • skullToxicity

    • To humans

      Rhododendron, including the 'Saint Merryn' variety, contains toxic compounds known as grayanotoxins. The ingestion of any part of the plant can be poisonous to humans. Symptoms of rhododendron poisoning may include vomiting, diarrhea, hypersalivation, weakness, coma, hypotension, CNS depression, cardiovascular collapse, and potentially death if consumed in large quantities. Immediate medical attention should be sought if ingestion occurs.

    • To pets

      Rhododendron is toxic to pets, with the 'Saint Merryn' variety containing grayanotoxins that can cause poisoning when ingested. Symptoms in pets may include vomiting, diarrhea, hypersalivation, weakness, coma, seizures, cardiovascular collapse, and potentially death, especially if a significant amount is consumed. Veterinary care is essential and urgent if a pet ingests any part of a rhododendron plant.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      5 feet (1.5 meters)

    • Spread

      5 feet (1.5 meters)

    • Plant type


    • Hardiness zones


    • Native area



  • money-bagGeneral Benefits

    • Ornamental Value: Rhododendron 'Saint Merryn' has vibrant flowers that add aesthetic value to landscapes and gardens.
    • Wildlife Attraction: Its blooms can attract pollinators such as bees, butterflies, and birds, supporting local ecosystems.
    • Shade Tolerance: The plant can thrive in partially shaded areas, making it versatile for garden design.
    • Seasonal Interest: It provides seasonal interest with its spring blooms and evergreen foliage, offering year-round garden appeal.
    • Erosion Control: The dense growth habit can help stabilize soil and control erosion on slopes.
    • Privacy: Can be used as a hedge or screening plant for increased privacy.

  • medicalMedical Properties

    This plant is not used for medical purposes.

  • windAir-purifying Qualities

    This plant is not specifically known for air purifying qualities.

  • leavesOther Uses

    • Rhododendron wood, being hard and dense, can be used for creating small decorative items like bowls, handles for tools, or even intricate carvings and inlays in woodworking projects.
    • The leaves of the Rhododendron can be used as a natural dye, giving wool and other natural fibers a range of tan to brown colors based on the mordant used.
    • Honey made from Rhododendron flowers can be distinct in taste, although it must be approached with caution due to potential toxicity.
    • Species related to Rhododendrons produce an essential oil that can be used in aromatherapy for its relaxing and calming properties.
    • Rhododendrons with larger leaves can be utilized as a natural mulch or composting material, contributing organic matter back to the soil.
    • In some cultures, various parts of Rhododendrons plants are used to produce natural insect repellents or deterrents for garden pests.
    • The thick foliage of Rhododendrons can provide cover and nesting opportunities for small birds and beneficial insects, thus promoting biodiversity.
    • The tannins present in Rhododendron can be extracted for use in the leather tanning industry as an alternative to synthetic tanning agents.
    • Rhododendron plants can be shaped into living fences or privacy screens due to their dense growth habit and attractive foliage.
    • Discarded stems and branches from Rhododendron trimming can be repurposed as natural supports or stakes in the garden for other plants.

Interesting Facts

  • bedFeng Shui

    The Rhododendron is not used in Feng Shui practice.

  • aquariusZodiac Sign Compitability

    The Rhododendron is not used in astrology practice.

  • spiralPlant Symbolism

    • Caution: Rhododendrons are known to be toxic, so they often symbolize a warning to be cautious or a reminder to respect nature's boundaries.
    • Beware of Danger: Because all parts of the plant are poisonous, it symbolizes the need to be wary of potential risks or threats.
    • Abundance: With their lush, voluminous blooms, rhododendrons can represent abundance and wealth.
    • Elegance: The beauty and grandeur of the rhododendron blooms are often associated with elegance and sophistication.
    • Survival: As rhododendrons can thrive in harsh mountainous environments, they can symbolize the ability to overcome adversity and survive in difficult conditions.
    • Rejuvenation: As many rhododendrons are spring bloomers, they can represent new beginnings and the rejuvenation of nature.
    • Homecoming: In some cultures, rhododendrons signify a return to home or a safe passage, likely because in the wild they are often found near mountain trails and passes.

Every 1-2 weeks
500 - 2500 Lux
Every 2-3 years
Late Winter to Early Spring
As needed
  • water dropWater

    Rhododendrons, including 'Saint Merryn', prefer consistently moist soil, so watering should be adjusted to maintain this condition without waterlogging the roots. Typically, watering deeply once a week with about 1 inch of water is sufficient, but this will vary with climatic conditions. During hot, dry periods, more frequent watering may be necessary. It's best to water in the morning, directly at the base of the plant, avoiding overhead watering to prevent fungal diseases. In winter, reduce watering but don't let the roots dry out completely.

  • sunLight

    Rhododendrons like 'Saint Merryn' thrive best in dappled shade or filtered sunlight. They do well in an eastern facing location where they can be protected from the harsh afternoon sun. They can also tolerate full sun in cooler climates if they are kept well-watered, but the light conditions must be carefully managed to prevent leaf scorch.

  • thermometerTemperature

    Rhododendrons like 'Saint Merryn' enjoy a range of temperatures from about 40°F to 70°F. They can survive minimum temperatures down to 10°F but should be protected from strong winds. Ideal temperature conditions are cool to moderate, as extreme heat can stress the plants.

  • scissorsPruning

    Prune 'Saint Merryn' rhododendrons to maintain shape and encourage bushier growth. The best time for pruning is soon after flowering, as next year's buds form shortly afterwards. Remove dead or diseased branches, and lightly shape the plant, being cautious not to cut into old wood which does not easily regenerate.

  • broomCleaning

    As needed

  • bambooSoil

    The best soil mix for Rhododendron 'Saint Merryn' is well-draining, high organic matter, and slightly acidic with a pH of 4.5 to 6.0. A combination of pine bark, peat moss, and perlite in equal parts can create an ideal environment for this plant.

  • plantRepotting

    Rhododendrons, including 'Saint Merryn', typically require repotting every 2 to 3 years or when the roots have filled the pot, to prevent them from becoming pot-bound and to replenish their soil.

  • water dropsHumidity & Misting

    Rhododendron 'Saint Merryn' prefers high humidity levels, ideally between 60-80%, to maintain glossy foliage and support overall health.

  • pinSuitable locations

    • Indoor

      Place in bright, indirect light and ensure high humidity.

    • Outdoor

      Plant in dappled shade with shelter from winds.

    • Hardiness zone

      5-8 USDA

  • circleLife cycle

    The life cycle of the Rhododendron 'Saint Merryn' begins with seed germination, where the seeds require a well-drained, acidic soil medium and appropriate moisture levels to sprout. Following germination, the seedling stage is characterized by initial growth of roots and shoots as the plant establishes itself. As the plant matures into the vegetative stage, it develops a robust root system and expansive green foliage, thriving in partially shaded environments. The rhododendron then reaches the flowering stage, typically in spring, where it produces clusters of vibrant flowers that attract pollinators, which is crucial for the cross-pollination necessary for seed production. After pollination, the plant produces seed capsules that eventually dry, release seeds, and complete the reproductive cycle. Throughout its life, the Rhododendron 'Saint Merryn' may undergo periods of dormancy during colder months, resuming growth with the return of favorable conditions.

  • sproutPropogation

    • Propogation time

      Late Winter to Early Spring

    • The most popular method for propagating Rhododendron 'Saint Merryn', which is commonly known as Rhododendron, is through semi-hardwood cuttings. This is usually done in the latter part of summer when the new growth has begun to mature and harden slightly. Select a healthy branch and cut a 4 to 6-inch (10 to 15 centimeters) section, making sure it has at least two sets of leaves. The lower set of leaves should be removed, and the cut end dipped in rooting hormone. Then, plant the cutting in a pot filled with a mixture of peat and perlite or a similar well-draining medium. To retain humidity, cover the pot with a plastic bag or a propagation dome and place it in a warm location with indirect light. Rooting typically takes several weeks after which the new Rhododendron plants can be potted individually.