Yakushima Rhododendron Rhododendron yakushimanum 'Koichiro Wada'

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


The Rhododendron 'Koichiro Wada' is known for its beautiful and ornamental features, often appreciated in gardens for its stunning blooms and foliage. It has a robust and dense growth habit, forming a rounded mound of evergreen leaves that provide year-round interest. The leaves of this plant are dark green, leathery, and have a distinctly thick and textured appearance with a coating that is sometimes described as being fuzzy or felt-like. The undersides of the leaves may be lighter in color, adding dimension to the plant's overall foliage. In the blooming season, which typically occurs in spring, the plant is adorned with spectacular flowers that are a draw for enthusiasts and gardeners alike. The flowers are typically large, trumpet-shaped, and arranged in showy clusters called trusses. Each individual flower exhibits a delicate pale pink to white color with occasional deeper pink spots or markings. The petals are waxy and give off a soft luster, contributing to the plant's delicate aesthetic. One of the distinctive features of the 'Koichiro Wada' is that its flower buds are often heavily coated in a dense, woolly indumentum which protects them over the winter months. As the buds burst open in the spring, they reveal the captivating display of blooms that have made this plant a beloved selection in many landscapes. Additionally, the inflorescence's initial pinkish tones may mature and fade to a pure, crisp white as they age, creating a mesmerizing gradient effect on the plant. This feature, along with the lush, evergreen foliage, makes the 'Koichiro Wada' a visually appealing plant that can add elegance to any setting. However, it is important to note that the overall impact of the plant's appearance will be influenced by its environment and the care it receives.

Plant Info
Common Problems

About this plant

  • memoNames

    • Family


    • Synonyms

      Yakushima Rhododendron, Koichiro Wada Rhododendron.

    • Common names

      Rhododendron yakushimanum 'Koichiro Wada'

  • skullToxicity

    • To humans

      Rhododendron, including the variety Rhododendron yakushimanum 'Koichiro Wada', contains grayanotoxins which are toxic to humans if ingested. Consumption of any part of the plant can lead to poisoning, with symptoms including vomiting, diarrhea, hypersalivation, weakness, and cardiac problems. In severe cases, ingestion can result in coma or death due to cardiovascular collapse.

    • To pets

      Rhododendron is toxic to pets, including cats and dogs. The toxins, known as grayanotoxins, can cause symptoms such as vomiting, drooling, diarrhea, hypotension, depression of the central nervous system, weakness, and in severe cases, life-threatening cardiovascular collapse. Prompt veterinary care is essential if a pet ingests any part of a rhododendron plant.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      3-4 feet (0.9-1.2 meters)

    • Spread

      3-4 feet (0.9-1.2 meters)

    • Plant type


    • Hardiness zones


    • Native area



  • money-bagGeneral Benefits

    • Ornamental Value: Yakushima rhododendron provides aesthetic appeal to gardens with its beautiful flowers and evergreen foliage.
    • Compact Growth: Suitable for small gardens due to its compact, rounded growth habit.
    • Cold Hardy: Can survive in colder climates, making it versatile for many landscapes.
    • Low Maintenance: Requires minimal pruning and is relatively easy to care for once established.
    • Drought Tolerance: Once established, it has moderate drought tolerance, reducing the need for frequent watering.
    • Attracts Pollinators: Flowers attract bees and butterflies, supporting local ecosystems.
    • Long Blooming Period: Provides a long season of interest with its blooms lasting several weeks.
    • Shade Tolerance: Can thrive in partial shade, offering flexibility in garden design.

  • 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 groundcover: Due to its dense foliage, 'Koichiro Wada' can be used as an effective groundcover, reducing soil erosion on slopes.
    • Habitat for wildlife: The thick leaves and structure provide shelter and nesting sites for various small birds and beneficial insects.
    • Photographic subject: The plant's picturesque blooms are a favorite subject for photographers and artists who specialize in botanical subjects.
    • Bonsai: Dwarf varieties of Rhododendron can be cultivated as bonsai specimens, artfully trimmed to create miniature landscapes.
    • Educational uses: Rhododendron species, including 'Koichiro Wada', are used in educational settings to teach botany and horticulture.
    • Landscape design: Used in Japanese garden design to represent mountains or natural hillscapes, enhancing aesthetic value and creating a serene environment.
    • Privacy screen: Because of its dense growth habit, it can be planted in rows to form a visual barrier and to help muffle sound.
    • Windbreaks: Rhododendron can be strategically planted to serve as windbreaks, protecting more fragile plants in the garden.
    • Cultural significance: In certain cultures, Rhododendrons are planted for their symbolic meanings, such as caution or wariness due to the toxic nature of their leaves.
    • Festivals and shows: Specimens like 'Koichiro Wada' are often featured at flower shows and horticultural events, attracting enthusiasts and collectors.

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

    • Beauty: The Rhododendron is often associated with beauty due to its large, showy blooms which make it a visually striking plant.
    • Caution: Some species of Rhododendron contain toxic substances and are considered poisonous if ingested, symbolizing caution and care.
    • Abundance: With its lush foliage and abundance of flowers, the Rhododendron can symbolize growth, prosperity, and abundance.
    • Rebirth: As a plant that blooms anew each season, the Rhododendron is sometimes seen as a symbol of rebirth and new beginnings.
    • Survival: Rhododendrons are known for their ability to survive in harsh conditions, often symbolizing hardiness and the ability to overcome challenges.

Every week
500 - 2500 Lux
Every 2-3 years
Spring-Early Summer
As needed
  • water dropWater

    The Yakushima rhododendron should be watered thoroughly, ensuring that the root ball is evenly moistened. It prefers consistently moist soil, so water the plant when the top inch of soil feels dry to the touch, which could be about once a week, depending on weather conditions. During the growing season in spring and summer, it may require more frequent watering, especially in dry periods. Generally, you might use about one gallon of water for a medium-sized plant each time you water. Reduce watering in the fall and further in the winter when the plant is dormant.

  • sunLight

    The Yakushima rhododendron thrives in dappled shade or partial sunlight. It should be placed in a location where it can receive morning sun and afternoon shade, as this mimics its natural habitat and conditions. Direct afternoon sunlight should be avoided as it can cause damage to the leaves.

  • thermometerTemperature

    The Yakushima rhododendron can tolerate a range of temperatures but thrives best when the weather is cool to moderate. It can generally withstand temperatures down to about 20 degrees Fahrenheit but should be protected from harsh winter winds. The ideal temperature range for this plant is between 50 and 75 degrees Fahrenheit for optimum growth.

  • scissorsPruning

    Prune the Yakushima rhododendron to maintain shape and encourage bushier growth, immediately after the spring blooming period is over. Remove any dead or diseased wood, and trim back overlong branches to a healthy bud. Pruning can be done annually or every other year, depending on the plant’s need for shaping.

  • broomCleaning

    As needed

  • bambooSoil

    Rhododendron yakushimanum 'Koichiro Wada', commonly known as Yakushima rhododendron, thrives in well-draining, acidic soil with a pH of 4.5 to 6.0. A mix of 50% pine bark, 30% peat moss, and 20% perlite or coarse sand is ideal for its growth.

  • plantRepotting

    Yakushima rhododendrons should be repotted about every two to three years. If growth appears to be stunted or the plant looks less vibrant, it may be time to repot it in a fresh soil mix.

  • water dropsHumidity & Misting

    Yakushima rhododendron prefers high humidity, ideally between 65-80%. To maintain adequate humidity, you can place it in a naturally humid environment or use a humidifier.

  • pinSuitable locations

    • Indoor

      Keep in bright, indirect light and high humidity.

    • Outdoor

      Provide dappled shade, shelter from winds, moist soil.

    • Hardiness zone

      5-8 USDA

  • circleLife cycle

    The Rhododendron yakushimanum 'Koichiro Wada', commonly known as the Yakushima Rhododendron, starts its life as a seed, which after dispersal and under right conditions will germinate and develop into a seedling. This plant's seedlings develop a root system and foliage, and as they mature into juveniles they begin to exhibit the characteristic woolly, whitish tomentum on the undersides of their leaves. As it enters the vegetative growth phase, the Yakushima Rhododendron undergoes several years of foliage expansion and root establishment, eventually reaching a mature shrub form recognized by its striking evergreen leaves and robust structure. The reproductive phase starts when the plant is mature enough to produce buds that will open into trusses of pink to white flowers, often with a distinctive blotch, typically occurring in mid to late spring. After pollination, seeds develop in capsules, which can be dispersed by wind when they ripen and split open in autumn, completing the life cycle. Pruning spent flowers and managing plant shape and health might occur at various points during the vegetative and reproductive phases if the plant is being cultivated in a garden setting.

  • sproutPropogation

    • Propogation time

      Spring-Early Summer

    • The Rhododendron yakushimanum 'Koichiro Wada', commonly referred to as the Yakushima Rhododendron, is typically propagated through semi-hardwood cuttings. The best time for taking cuttings is in the late summer after the blooms have faded and the new growth has begun to mature but is not yet fully hardened. The ideal length for cuttings is about 4 to 6 inches (approximately 10 to 15 centimeters). After cutting, the lower leaves are removed, and the base of the cutting is treated with a rooting hormone to encourage root development. The cuttings are then placed in a well-draining medium, such as a mix of perlite and peat, ensuring the environment is kept humid and with indirect but bright light. The cutting typically roots in 2 to 3 months, after which it can be gradually acclimatized to less humid conditions before being potted on or planted out.