Understanding Rowan: A Brief Overview
The rowan tree, or mountain ash, is a small deciduous tree that produces white flowers in the spring and red berries in the autumn. It can grow up to 15-30 feet in height. Rowan trees are popular ornamental trees that provide seasonal interest and food for wildlife. According to the Woodland Trust, the rowan “has a long history in folklore, poetry and practical uses”.
Rowan trees prefer acidic, well-drained soil and full sun exposure for at least six hours per day. They are relatively low-maintenance, cold-hardy trees that thrive in temperate climates. The most common species is the European rowan (Sorbus aucuparia), which produces orange-red berries. The berries are a favorite food source for many birds and small mammals during winter. Though the berries are bitter to humans, they are sometimes used to make jelly or alcoholic spirits.
Rowan trees have a fast growth rate and can live 50-200 years depending on the species. Their dense canopy provides shade in summer and vibrant fall color. Rowan trees require little pruning, but should be inspected regularly for common pests and diseases like canker, rust, and sawfly larvae. With proper care and maintenance, rowan trees can make a beautiful and long-lasting addition to any landscape.
Choosing the Right Spot for Your Rowan Tree
Selecting an appropriate planting site is one of the most important steps to ensure your rowan tree thrives. Rowan trees require full sun exposure for at least six to eight hours per day, so choose a spot in your garden that is not shaded by buildings or other trees. Rowan trees can tolerate partial shade, but will produce fewer flower clusters and berries if they do not receive adequate light.
Rowan trees prefer well-drained, acidic soil with a pH between 4 and 6. Heavy, alkaline soils do not provide the proper conditions for healthy root growth and may lead to root rot. Before planting, test your soil to determine the acidity level and nutrient content. The ideal soil will be loamy or sandy and contain moderate amounts of phosphorus, potassium, and organic matter. If your soil’s pH is not in the proper range or lacks certain nutrients, it may require amendments such as compost or peat moss to adjust acidity and improve structure.
Rowan trees have relatively shallow root systems, so choose a spot that will give the roots ample room to spread out. Do not plant rowan trees in confined spaces or near walkways, drives, or buildings where root growth may cause disturbance. The mature size of the rowan tree species you select will also determine the minimum planting space required. Most rowan cultivars are well suited to small and medium-sized gardens, but may become too large for very small spaces.
In addition to light and soil requirements, consider your rowan tree’s visual characteristics when determining the ideal planting spot. Rowan trees are prized for their seasonal displays of white flowers and bright red berries, so place them in a prominent area of your garden where they can be fully appreciated. Hardy and relatively low-maintenance, rowan trees make an excellent choice for adding graceful beauty to entryways, property lines, or natural dividers in the landscape. With the proper site selection, rowan trees will thrive and enhance your outdoor space for generations.
Preparing Your Soil for Rowan Planting
To ensure your rowan tree gets off to a healthy start, preparing the soil before planting is essential. Rowan trees prefer well-drained, acidic soil with a pH between 4 and 6. If a soil test reveals that your soil is alkaline (above pH 7) or lacks certain nutrients like phosphorus or potassium, amendments may be needed to adjust the acidity and fertility before planting.
Adding compost or peat moss will help increase soil acidity and improve structure. For heavily alkaline soils, elemental sulfur may also be used to lower pH according to the recommendations on the product packaging. The target pH for rowan trees is between 5 and 6. Check your soil again after amendments have been added to ensure the proper acidity level before planting.
Moderate amounts of compost will also help provide nutrients for healthy root establishment and growth. For new plantings, incorporate 2 to 3 inches of compost into the top 6 to 8 inches of soil over the entire planting area. In addition to compost, you may need to add supplements of bone meal, blood meal, or kelp meal to increase phosphorus and potassium levels based on soil test results. Thoroughly mixing amendments into the soil before planting will allow rows roots to access nutrients from the surrounding area.
Another important aspect of soil preparation is improving drainage if needed. Rowan trees do not tolerate standing water and root systems are prone to disease in waterlogged soils. If your soil’s drainage is poor, it should be amended before planting. Work 2 to 3 inches of compost and 1/3 volume of perlite into the top 8 to 12 inches of soil to create a well-drained, loamy texture ideal for rowan trees. Perlite is a naturally occurring volcanic glass that will help increase pore space and improve drainage without altering soil chemistry.
With the proper site selection and thorough soil preparation, rowan trees will have the best possible start in your landscape. Taking time to ensure suitable acidity, adequate nutrients, and excellent drainage before planting will support healthy root establishment and robust growth of your rowan tree for years to come.
Planting Your Rowan Tree: Step-by-Step Guide
Once you have selected an appropriate site and prepared the soil, you are ready to plant your rowan tree. For the best results, follow these step-by-step planting instructions carefully:
- Dig a hole two to three times the width of the root ball and slightly shallower than the depth of the root ball. Creating a wide planting hole will give rowan roots ample room to establish and grow. Measure the root ball before digging to ensure proper sizing of the hole.
- Place the root ball in the hole and check that it is level with the surrounding soil. The root flare, where the roots meet the trunk, should be at or slightly above the soil surface. If needed, remove soil from under the root ball until level.
- Backfill the hole around the root ball, tamping down gently with your foot as you add soil to eliminate any air pockets. Do not compact the soil too firmly, as rowan roots still require oxygen.
- Water thoroughly immediately after planting. Provide 5 to 10 gallons of water for a newly planted rowan tree. Add moisture-retaining mulch such as compost or wood chips around the base of the tree in a circle at least 3 to 4 feet in diameter.
- Prune only dead or damaged branches at the time of planting. Avoid heavy pruning, as it can stress the tree at establishment. Any pruning should be done before the rowan tree begins active growth in spring.
6. Staking the rowan tree after planting will help provide stability until the roots have anchored in the surrounding soil, which typically takes 1 to 2 years. Use 2 to 3 stakes evenly spaced around the outside of the root ball, driven at least 2 feet into the ground for secure support.
- Fertilize your newly planted rowan tree if recommended based on your soil test results. Use a balanced, slow-release tree fertilizer to provide nutrients for healthy establishment. Follow directions on the product packaging for proper application rates and timing.
By carefully following planting and aftercare guidelines, your rowan tree will have the best start in your landscape. Though rowan trees are relatively low-maintenance, paying attention to details like proper planting depth, irrigation, mulching, and fertilization after planting will support vigorous growth and development. With time and care, your rowan tree will thrive and provide year-round beauty for generations.
Caring for Your Rowan Tree: Watering, Fertilizing, and Pruning
Proper care and maintenance will keep your rowan tree healthy and help it reach full potential. The primary needs of rowan trees after planting include:
Watering: Water rowan trees regularly, especially for the first 3 to 5 years after planting while roots are establishing. Rowan trees need at least 1 to 2 inches of water per week. Water soak the entire root zone beneath the tree canopy. The soil should dry slightly between waterings but not completely. Monitor soil moisture to determine when watering is needed.
Fertilizing: If recommended based on your soil test results, fertilize rowan trees in early spring before buds open. Use a balanced, nitrogen-based fertilizer formulated for trees and shrubs at the recommended rate. Do not over-fertilize, as it can lead to disease and pest problems.
Pruning: Rowan trees require little pruning to maintain their naturally rounded shape. Only remove dead, damaged, or crossed branches at their point of origin using sharp pruning shears or a pruning saw. Avoid heavy pruning, as it can reduce flower and berry production and stress the tree. Some minor shaping can be done in late winter or early spring before active growth begins for the season.
Rowan trees are relatively low-maintenance, but annual inspections should be conducted to monitor for common issues and ensure optimal health. Some potential problems to watch for include:
• Drought stress: Excessively dry soil can weaken rowan trees and make them more susceptible to disease and insect pests. Water thoroughly if drought stress is observed.
• Nutrient deficiencies: Discoloration or stunting of leaves may indicate a lack of certain nutrients. Have a soil test done to determine any deficiencies and recommended corrections before fertilizing.
• Canker: Bark lesions that ooze sap and kill branches. Prune out infected areas and improve air circulation and light exposure. Fungicides may be recommended for severe infections.
• Leaf spots: Various fungi can cause spotting and dieback of leaves. Remove infected foliage and mulch to prevent spread. Apply fungicides if widespread damage occurs.
• Aphids: Suck insect pests that feed on leaves, buds, and berries, causing distortion and drop. Apply insecticidal soap, horticultural oil, or spinosad spray to infested areas.
With attentive care and monitoring, common issues that afflict rowan trees can be prevented or treated to avoid significant impacts on health, growth, and aesthetic quality. Over time, your well-maintained rowan tree will grow into a beautiful focal point in the landscape for years to come.
Protecting Your Rowan Tree from Common Pests and Diseases
While rowan trees are relatively low-maintenance, there are certain pests, diseases, and other problems to be aware of. Regular monitoring and prompt treatment can help avoid damage and ensure your rowan tree stays in optimal health. Some of the most common issues affecting rowan trees include:
Canker: Bark lesions caused by fungi that girdle branches and kill plant tissue. Prune out infected wood, improve air circulation, and apply fungicides containing copper or bordeaux mixture.
Leaf spots: Fungal diseases that cause spotting, browning and premature leaf drop. Rake up and dispose of fallen foliage to prevent spread. Treat with fungicides if severe.
Rust: Orange, powdery fungal spores found on the undersides of leaves. Can cause early leaf drop. Apply fungicides and improve air circulation and light exposure.
Sawfly larvae: Caterpillar-like larvae that feed on rowan leaves, causing skeletonization and defoliation. Apply insecticidal soap, spinosad, or bifenthrin to infested foliage.
Aphids: Sap-sucking insects that feed on buds, leaves, and berries. Secrete honeydew that promotes sooty mold growth. Apply insecticidal soap, horticultural oil, or spinosad for control.
In addition to disease and pest problems, rowan trees can also suffer damage from environmental factors with if left unaddressed. Some issues to monitor for include:
• Drought stress: Lack of sufficient water can weaken the rowan tree and make it more susceptible to health issues. Water thoroughly if drought stress is observed.
• Nutrient deficiencies: Yellowing or stunted leaves may indicate a lack of nutrients like nitrogen, iron or manganese. Have a soil test done to determine any deficiencies and treatment needed.
• Mechanical damage: Broken or torn branches can become entry points for disease and insect pests. Prune away any damaged tissue and seal wounds with pruning paint.
• Rodent damage: Chewed bark at the base of the trunk or on exposed roots. Install a rodent guard or wire mesh around the trunk for protection.
With regular inspections, you can prevent common problems from significantly impacting your rowan tree. Take action quickly if any disease, pest, or other issue is observed to avoid damage and support long term health and beauty. With proper care and management, your rowan tree will thrive for generations to come.