Joseph Rock Mountain Ash Sorbus 'Joseph Rock'

👤 Non-toxic to humans
🐾 Non-toxic to pets
🌸 Blooming
🍪 Edible
‍🌱 Easy-care
mountain ash 'Joseph Rock'


Sorbus 'Joseph Rock' is an attractive deciduous tree known for its beautiful foliage and vibrant fruit. The leaves of this plant are pinnate, meaning they have small leaflets arranged on either side of a central stem, and they emerge as a fresh green color in the spring. As the season progresses, the foliage undergoes a dramatic transformation, turning into shades of vibrant red, orange, and purple before falling in autumn. In spring, the tree is adorned with clusters of creamy white flowers, which are quite conspicuous and give the tree a decorative look. These flowers are not only a visual highlight but also attract various pollinators to the garden. As the blossoms fade, they are replaced by bunches of berries, which are one of the most distinctive features of 'Joseph Rock'. The berries start off green but gradually mature to a rich, amber-yellow hue that stands out against the tree's foliage. These berry clusters remain on the tree well into the winter, providing a striking visual contrast with the bare branches. The bark of Sorbus 'Joseph Rock' contributes to its ornamental value. It has a textured appearance that becomes more pronounced with age, adding character to the tree throughout the year. Overall, Sorbus 'Joseph Rock' is a showy plant that goes through a captivating series of changes throughout the seasons, providing lasting interest in a garden setting with its lush foliage, attractive flowers, colorful berries, and textured bark.

Plant Info
Common Problems

About this plant

  • memoNames

    • Family


    • Synonyms

      Joseph Rock Mountain Ash, Joseph Rock Rowan, Joseph Rock Whitebeam.

    • Common names

      Sorbus 'Joseph Rock'.

  • skullToxicity

    • To humans

      Sorbus 'Joseph Rock', commonly known as Rowan, is not widely known for being toxic to humans. However, it is important to note that the seeds inside the berries contain a compound known as amygdalin, which can release cyanide when metabolized. Ingesting large quantities of Rowan berries, especially if the seeds are chewed or swallowed, can potentially lead to cyanide poisoning. Symptoms of cyanide poisoning can include headache, nausea, vomiting, stomach cramps, dizziness, and weakness. In severe cases, cyanide can lead to respiratory failure and even death. Thus, while the berries are not considered highly toxic when consumed in small amounts, care should be taken to avoid ingesting large quantities of seeds.

    • To pets

      Rowan, also known as Sorbus 'Joseph Rock', does not have a well-documented history of toxicity in pets such as cats and dogs. Much like with humans, the seeds of the berries contain compounds that can release cyanide. If pets consume a large number of berries with seeds intact, they could experience symptoms of cyanide poisoning, which may include vomiting, diarrhea, difficulty breathing, seizures, and potentially, in severe cases, death. To prevent any risk to pets, it is advisable to prevent access to and ingestion of large quantities of the berries, particularly the seeds.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      20-25 feet (6-7.5 meters)

    • Spread

      15 feet (4.5 meters)

    • Plant type


    • Hardiness zones


    • Native area



  • money-bagGeneral Benefits

    • Ornamental Appeal: Sorbus 'Joseph Rock' is known for its aesthetic value, including white flowers in spring and bright yellow berries in autumn.
    • Wildlife Attraction: The berries provide a food source for birds, especially in winter months when food is scarce.
    • Shade Provider: With its broad canopy, it can offer a pleasant shade in gardens and parks, making it a practical choice for landscape design.
    • Seasonal Interest: This plant has year-round interest with flowers in spring, berries in autumn, and foliage that changes from green to various shades of orange, red, or purple before dropping in winter.
    • Erosion Control: The root system helps to stabilize soil, which can be particularly helpful on slopes or in areas prone to erosion.
    • Urban Tolerance: It can withstand urban pollution and is often planted as a street or avenue tree in cities.
    • Low Maintenance: Once established, it requires minimal care, making it suitable for gardeners of all levels of experience.

  • 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

    • The berries of the Mountain Ash can be used to make natural dyes for fabric, yielding colors from green to yellow depending on the mordant used.
    • Wood from the Mountain Ash is sometimes used in woodworking for decorative items due to its fine grain and workability.
    • In some cultures, the Mountain Ash is planted in gardens and parks as a symbol of good luck and to ward off evil spirits.
    • The wood is suitable for crafting small wooden tools or handles, where a strong, but not overly heavy, wood is needed.
    • The tree's wood can also be used in the production of musical instruments such as recorders or woodwinds because of its acoustic properties.
    • Floral arrangements and wreaths sometimes incorporate Mountain Ash berries for their bright color and persistence after cutting.
    • Due to its dense growth habit, the Mountain Ash can be pruned and trained into living fences or privacy screens in landscapes.
    • The tree can be used as a natural dye in the leather tanning process, providing subtle color variations to the finished product.
    • In some countries, the berries are used in the distillation of certain alcoholic beverages to impart flavor and color.
    • Mountain Ash timber is sometimes used in turnery for making intricate objects on a lathe, such as chess pieces or decorative bowls.

Interesting Facts

  • bedFeng Shui

    The Mountain Ash is not used in Feng Shui practice.

  • aquariusZodiac Sign Compitability

    The Mountain Ash is not used in astrology practice.

  • spiralPlant Symbolism

    • Protection: The Sorbus commonly symbolizes protection as it was believed to guard against enchantment and ward off malevolent spirits.
    • Wisdom: In various cultural mythologies, trees like the Sorbus are associated with wisdom due to their longevity and the observation of the cycles of nature.
    • Survival: As the Sorbus can grow in harsh conditions, it often symbolizes survival and the ability to thrive despite challenges.
    • Transition: The Sorbus, with its bright berries and autumn foliage, symbolizes change and transition, as it clearly marks the changing seasons.

Every 1-2 weeks
2500 - 10000 Lux
Not needed
Late winter
As needed
  • water dropWater

    Mountain Ash trees, such as Sorbus 'Joseph Rock', prefer well-drained soil and do not like to be waterlogged. When the tree is young, it's important to water it regularly to ensure a good establishment. Provide about 15-20 gallons of water per week during the growing season, reducing in cooler weather to encourage the tree to harden off for winter. It is best to check the soil moisture weekly; if the top 2-3 inches of soil are dry, it's time to water again. Mature trees are quite drought tolerant but may benefit from occasional deep watering during prolonged dry periods.

  • sunLight

    The Mountain Ash thrives best in full sun to partial shade. For optimal growth and health, plant it where it can receive at least six hours of direct sunlight daily. These trees are versatile and can tolerate a bit of shade, but too much shade can lead to reduced flowering and fruiting, as well as increased susceptibility to pests and diseases.

  • thermometerTemperature

    Sorbus 'Joseph Rock', or Mountain Ash, is hardy and can withstand a wide range of temperatures, from cold winters to moderate summers. The plant can survive in temperatures as low as -30°F and as high as 85°F, but it prefers the cooler end of this spectrum. The ideal temperature range for the Mountain Ash is between 50°F and 70°F.

  • scissorsPruning

    Pruning the Mountain Ash is typically done to remove dead or diseased wood, to shape the tree, and to promote better air circulation within the canopy. Prune during the dormant season, late winter or early spring, before new growth starts. Every year, check for damaged branches to remove, but a more thorough pruning can be done every few years as needed. Avoid excessive pruning, which can stimulate too much new growth and weaken the tree.

  • broomCleaning

    Not needed

  • bambooSoil

    The Mountain Ash or Sorbus 'Joseph Rock' prefers well-draining, loamy soil with a slightly acidic to neutral pH between 5.5 and 7.0. The best soil mix can be created by combining two parts loam, one part peat, and one part sand or perlite, ensuring good drainage and aeration for the roots.

  • plantRepotting

    Mountain Ash trees like Sorbus 'Joseph Rock' generally do not require frequent repotting as they are outdoor plants. They may only need replanting or transferring if they outgrow their space or for cultivation reasons.

  • water dropsHumidity & Misting

    Sorbus 'Joseph Rock', commonly known as Mountain Ash, is tolerant of a wide range of humidity levels and does well in the natural humidity of outdoor environments.

  • pinSuitable locations

    • Indoor

      It's unsuitable; Mountain Ash is a large tree for outdoor planting only.

    • Outdoor

      Plant in well-draining soil, full sun to partial shade. Not ideal for small gardens.

    • Hardiness zone

      5-7 USDA

  • circleLife cycle

    The life cycle of Sorbus 'Joseph Rock', commonly known as Joseph's Rock Mountain Ash, begins with the germination of the seeds which typically occurs in the spring following a period of cold stratification that breaks the seed dormancy. The seedling stage is characterized by the emergence of the first leaves and a primary root, which will develop into a small sapling. Over the next several years, the sapling will gradually mature into a young tree, developing its characteristic pinnate leaves and beginning to form its structural shape. Once the tree reaches maturity, it will start to produce clusters of white blossoms in late spring, which are followed by the appearance of its distinctive yellow-to-orange berries in the fall. The tree will continue to flower and fruit annually, which is an essential part of its reproductive cycle. As it ages, the tree will eventually reach senescence and its growth will slow, leading to a decline in health and productivity until it dies.

  • sproutPropogation

    • Propogation time

      Late winter

    • The most popular method of propagation for the Mountain Ash, specifically the Sorbus 'Joseph Rock', is by seed. Typically, this process begins in the fall after the berries have ripened and seeds have been collected. Seeds require a period of cold stratification to break dormancy, which involves mixing the seeds with moist sand and storing them in a refrigerator for approximately 90 to 120 days (2°C to 5°C). After stratification, seeds can be sown in pots or a nursery bed, usually in the spring. It can take one to two years for seedlings to become sturdy enough for transplanting into their final location.