Mountain Ash Sorbus glabriuscula

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


Sorbus glabriuscula, commonly known as the Smooth Mountain Ash, is a stunning deciduous tree known for its compound, softly textured leaves and delicate clusters of blossoms. The leaves are pinnate, meaning they have multiple leaflets arranged on either side of a central stem. Each leaflet is oval with a finely serrated edge, creating an elegant feather-like appearance. In spring and early summer, the Smooth Mountain Ash graces the landscape with clusters of small white flowers. These flowers are arranged in dense, flat-topped clusters that provide a striking contrast against the bright green of the new foliage. As the seasons progress, these blossoms give way to eye-catching berries. The berries are a vivid red or orange and often persist into winter, providing a touch of color in the bare landscape and a food source for birds and wildlife. The bark of the Smooth Mountain Ash is smooth and gray, lending a refined look to the tree's trunk and branches even after the leaves have fallen. Distinctly, the presence of the Smooth Mountain Ash can be noted also by its growth form, which integrates into various landscapes, contributing to the plant's allure in gardens, parks, and natural wooded areas. Overall, the Smooth Mountain Ash's visual features—including its composite leaves, attractive flowers, and colorful berries—make it a picturesque addition to any setting where it is grown.

Plant Info
Common Problems

About this plant

  • memoNames

    • Family


    • Synonyms

      Smooth Rock Whitebeam, Coast Rock-Whitebeam, American Mountain-Ash

    • Common names

      Pyrus glabriuscula, Aria glabriuscula.

  • skullToxicity

    • To humans

      Sorbus glabriuscula, commonly known as Smooth Mountain Ash, is not widely recognized for having toxic effects on humans. Typically, members of the Sorbus genus produce fruits that can be consumed when ripe and properly prepared, often used in jellies or similar culinary applications. However, unripe or improperly prepared fruits can cause digestive discomfort, including stomach aches, nausea, or diarrhea. Care should always be taken when identifying and preparing wild edibles to avoid these negative effects.

    • To pets

      Similar to its effects on humans, Smooth Mountain Ash (Sorbus glabriuscula) is not generally considered highly toxic to pets. However, the consumption of unripe fruits or large quantities of the plant material may lead to gastrointestinal upset in animals, presenting as vomiting or diarrhea. As pets can have unique sensitivities, it's advisable to prevent them from ingesting the plant, and if they do, to monitor for any adverse reactions and consult a veterinarian if symptoms occur.

  • infoCharacteristics

    • Life cycle


    • Foliage type


    • Color of leaves


    • Flower color


    • Height

      10-20 feet (3-6 meters)

    • Spread

      10-15 feet (3-4.5 meters)

    • Plant type


    • Hardiness zones


    • Native area

      North America


  • money-bagGeneral Benefits

    • Ecosystem support: Sorbus glabriuscula, commonly known as Smooth Mountain Ash, provides food in the form of berries for various bird species and mammals.
    • Ornamental value: With its attractive white flowers and red/orange berries, it adds aesthetic appeal to gardens and parks.
    • Habitat creation: This plant creates a microhabitat for small insects and other fauna, promoting biodiversity.
    • Soil stabilization: The root system can help prevent soil erosion, particularly in sloped areas.
    • Seasonal interest: It offers year-round visual interest, with flowers in spring, berries in late summer through fall, and sometimes colorful autumn foliage.
    • Climate adaptability: Being native to cooler climates, it's suitable for gardens in similar conditions where other plants might not thrive.
    • Windbreak: When planted in groups, Smooth Mountain Ash can act as a windbreak to protect more sensitive plants or areas.
    • Shade provision: While not a large tree, it can provide a moderate amount of shade for underplantings or small sitting areas.

  • 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

    • Sorbus glabriuscula, commonly known as the Mountain Ash, can be used for bonsai due to its small leaves and attractive branching patterns.
    • The wood of Mountain Ash is often used for carving and turning as it is relatively hard and has a fine grain, making it ideal for detailed work.
    • In woodworking, the timber from Mountain Ash is sometimes used to make tool handles because of its strength and durability.
    • The berries of Mountain Ash can be used to make natural dyes, providing colors ranging from orange to pink or purple.
    • The tree's compact size makes it suitable for urban landscaping, providing ornamental value in small garden spaces.
    • Mountain Ash can be planted as a windbreak in rural gardens or farms, thanks to its hardy nature and resistance to cold climates.
    • The tree's dense canopy offers habitat and nesting opportunities for various bird species, enhancing local biodiversity.
    • The attractive fall colors of Mountain Ash foliage can be used in dried flower arrangements and autumnal decorations.
    • During winter months, the persistent fruits serve as a food source for birds, making the plant valuable for wildlife gardens.
    • Its adaptable growth habit allows it to be used for slope stabilization and erosion control in landscape management.

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 - Sorbus glabriuscula, commonly known as Mountain Ash or Rowan, has been traditionally believed to ward off evil and provide protection. This belief possibly stems from the tree's ability to survive in harsh, high-altitude environments, symbolizing resilience against adversity.
    • Wisdom - The Rowan tree is often associated with knowledge and wisdom. In mythology, it is sometimes considered a tree of divination, with its bright berries symbolizing the fruits of insight.
    • Life and Vitality - With its vibrant red berries and lush foliage, the Mountain Ash represents life and vigor. The berries mature in the late summer and sustain many bird species, emphasizing the tree's role in nurturing life.
    • Guidance and Protection in Journeys - There is a belief that carrying a piece of Rowan wood was a safeguard for travelers on journeys, offering them direction and safety.

Every 2-3 weeks
2500 - 10000 Lux
Every 2-3 years
Spring-Early Summer
As needed
  • water dropWater

    The Mountain Ash should be watered regularly, with a deep watering once a week, providing approximately 1 to 1.5 gallons per watering for young trees, and more for established trees depending on the tree size and environmental conditions. It is important to avoid overwatering and ensure that the soil is well-draining, but also maintaining consistent moisture, especially during hot, dry periods. In the fall, watering can be reduced, and during winter months, the tree may only need supplemental watering if there are extended dry spells.

  • sunLight

    The Mountain Ash thrives best in full sun to partial shade. It should be planted in a spot where it can receive at least six hours of direct sunlight daily, but it can also tolerate some shade, particularly in the hotter part of the day. Avoid placing it in deep shade, as this will hinder its growth and fruit production.

  • thermometerTemperature

    The Mountain Ash is hardy and adapts well to a range of temperatures but prefers a cooler climate. It can survive minimum temperatures down to around -30 degrees Fahrenheit and can handle maximum temperatures up to about 90 degrees Fahrenheit. The ideal temperature range for Sorbus glabriuscula would be between 50 to 70 degrees Fahrenheit, with cooler temperatures being particularly favorable during the dormant winter period.

  • scissorsPruning

    The Mountain Ash should be pruned to maintain its shape and remove any dead, diseased, or damaged branches. The best time for pruning is in late winter or early spring before new growth begins. Pruning can be done annually, focusing on thinning out crowded branches to allow light and air to penetrate the canopy, which helps in preventing disease and encouraging a strong, healthy structure.

  • broomCleaning

    As needed

  • bambooSoil

    The Mountain Ash or Rowan prefers a well-draining, loamy soil with a pH ranging from slightly acidic to neutral (pH 5.5-7). The best soil mix can be achieved by blending equal parts of garden soil, peat, and perlite or sand to ensure good drainage and aeration.

  • plantRepotting

    Mountain Ashes generally do not need frequent repotting and can be done every 3-5 years. They can be repotted in spring before new growth begins, ensuring minimal disruption to the plant.

  • water dropsHumidity & Misting

    Mountain Ash trees, being hardy, do not require high humidity levels and can thrive in average outdoor humidity conditions.

  • pinSuitable locations

    • Indoor

      Ensure bright light, cool temperatures, and some humidity for indoor growth.

    • Outdoor

      Plant in well-draining soil with sun to partial shade exposure.

    • Hardiness zone

      4-7 USDA

  • circleLife cycle

    Sorbus glabriuscula, also known as the Mountain Ash or Rowan, begins its life cycle with seed germination, which requires a period of cold stratification to break dormancy. Seedlings emerge and grow into saplings, developing a root system and foliage, predominantly in the spring. As the plant matures, a woody stem and branching pattern establish, leading to the development of a small to medium-sized tree. Seasonally, the Mountain Ash produces clusters of white flowers, typically in late spring, which are then pollinated by insects. Following pollination, these flowers develop into bright red berries by late summer, which are food sources for birds and other wildlife, aiding in seed dispersal. The tree goes through a period of dormancy in winter, with leaves dropping, and the cycle is repeated each year.

  • sproutPropogation

    • Propogation time

      Spring-Early Summer

    • Propogation: The Mountain Ash, known botanically as Sorbus glabriuscula, is typically propagated via seed, although it can also be propagated by cuttings or grafting. To propagate by seed, the most popular method, seeds should be collected in the fall after the fruit has ripened. They often require a period of cold stratification—being subjected to cold, moist conditions for 60 to 90 days—to break dormancy and improve germination rates. This can be accomplished by mixing the seeds with moist sand and storing them in a refrigerator at 33-41°F (0.5-5°C). After stratification, the seeds are usually sown in a well-draining soil mix in pots or flats and placed in a cold frame or greenhouse in early spring. Seedlings typically emerge within a few weeks and can be transplanted outdoors once they are strong enough and the danger of frost has passed.