Mountain Ash Sorbus: Different Types, Features, Growth Guide

Mountain ash

Though called the Mountain Ash, it is not a type of ash tree. Instead, it is a member of the rose family. Native to North America, you can find them in several different habitats. But, it is prevalent in the mountains around the rock outcrops and the forests. The mountain ash Sorbus or the Sorbus aucuparia is one of the most widely planted of a large group of similar trees and shrubs.

It is a small plant with dark green colored leaves that change their color to reddish-purple, orange, and yellow in the fall. Also known as Rowans, these are deciduous, attractive, ornamental trees that are an ideal pick for small or average-sized gardens.

In spring, they are covered with showy white flowers, followed by giant clusters of berry-like flaming red-hued fruits that the birds and other wildlife love. Since it is susceptible to pests, diseases, and fire, Sorbus mountain ash trees are relatively short-lived.

Mountain Ash Snapshot

Native to	Northern Hemisphere and distributed in temperate Eurasia and North America from Newfoundland to Georgia.
Botanically Called	Sorbus aucuparia
Hardiness Zones	They grow through USDA hardiness zones two through five.
Size	They grow between 10 and 30′ with a spread of around 15′ at maturity.
Growth rate	Mountain ash tree growth rate is slow. Its height increases at less than 12″ per year.
Sun	The tree thrives in full sun or partial shade. But, it demands at least four hours of unfiltered sunlight every day.
Flowers	Showy white flowers that usually pop in early summer or late spring.
Soil	It prefers acidic, loamy, moist, sandy, well-drained, wet, and clay soils.
Fruits	Small, red, or orange-red berry-like fruits
Leaves	It may have spear-shaped of 1½–4″ in length or oblong-shaped leaves that are 12″ long with 11-17 leaflets.

How Do I Identify A Mountain Ash Tree?

The Mountain ash Sorbus is not a part of the Ash tree family. The Mountain Ash is from the same species as the rose bush, the Rosaceae. Even though some types of mountain ash trees have a more traditional tree-like form, many have a shrub-like appearance. The former grow tall at 50 feet. Typically, Mountain ash has some distinctive characteristics:

1. Branches and buds – Intertwined across each other, they do not alternate along the stems. But, the branches and the buds tend to die. So, not every branch will have a counterpart.

2. Flowers – Most varieties have giant clusters of white flowers that blossom in the spring. Every flower has five petals.

3. Bark – The mountain ash is smooth and has a gray bark with an orange cast. Most of them have abrasions. In the established tree, the bark changes its color to brownish-gray and forms diamond-shaped ridges.

4. Leaves – Most types of mountain ashes have compound leaves with fifteen small leaflets. Some mountain ash Sorbus varieties are long pinnate, approximately nine inches. Typically, all categories have dark green-hued leaves in summer and spring. However, they change their color to a bright blend of orange, red, and yellow in the fall.

On the base, the leaves are lighter. Most species have serrated leaflet margins with all leaflets arranged opposite one another, except for the one at its base.

5. Fruits – You will see most kinds of Mountain Ash with berry-like fruits in orange-red colors. Harvested in the fall, the different types of mountain ash trees have varied colored fruits, ranging from bright orange to beach, pink, yellow, red, and white. Though edible, the fruits are acidic and do not have a very delectable flavor.

6. Seeds – In these trees, the individual seeds are packed in the samaras and appear in clusters. They all have a single wing and remain attached to the tree till winter.

Growing Tips

The growing tips and care guide for these trees will vary depending on where you live. Ideally, the plant demands a cool climate and despises humid summers for an excellent mountain ash tree growth rate.

The plant thrives in USDA hardiness zones two through five. Mountain ash can tolerate shade, but they enjoy full sun. So, plant it accordingly. Choosing the right location is vital for mountain ash care. Though forgiving, the mountain ash cannot tolerate compacted soil, drought, pollution, flooding, salt, or heated areas.

So, if you opt for an area sans these concerns, your mountain ash will live long.

A. When to plant?

Plant the bare-root rowans in the growing months from November to March. However, if grown in containers or pots, you can plant them any time of the year, but not during the summers. When you plan them in colder months, it helps Mountain Ash settle well before the commencement of the growing season.

B. Mandatory soil assessment test

Before you dig the plant, conduct a soil test to ensure that the plant grows in acidic soil with 4.5 to 6 pH. If not, you can add amendments to make the soil more acidic. Ideally, the soil should be well-draining and moist.

C. Pruning

Sorbus mountain ash trees are a plant with minimum pruning needs. You can remove the diseased, dead, or dying growth to thin the plant. Also, conduct pruning strictly in early spring or late autumn.

Different Types of Mountain Ash Trees

Here is a list of their different varieties:

1. Sorbus:- ‘Eastern Promise’ is a pink-berried Mountain Ash. It is a beautiful, small tree, suitable for smaller gardens. This rounded tree yields small white flowers in clusters during spring. The plant has dark green leaves, which become orange and deep purple as they approach autumn and change to orange before they leave the plants.

It is a deciduous tree. This mountain ash Sorbus is a forgiving plant. So, you can plant it in various soil types. But, if you wish for this plant to thrive, you must grow it in well-drained, moist soil in partial shade or full sun.

2. Sorbus Aucuparia:- Rowan, mountain ash, or European Mountain ash is a deciduous variety. It is a shrub from the rose family and is an incredibly variable species. It comprises the trees native to Europe, Africa, and Asia.

It is a frost-hardy plant that is not demanding in maintenance. These types of mountain ash trees produce white flowers in clusters in spring, followed by yellow autumn leaves and red berries.

3. Sorbus Reducta:- It is a deciduous, small suckering shrub. This plant yields leaves, which have a maximum of fifteen glossy dark green, toothed leaflets that change their color to purple in autumn. They produce white flower clusters, followed by pink and then white fruits.

Sorbus ‘Joseph Rock’ is the ideal specimen for small yards and gardens. It is an upright tree with pinnate leaves. As autumn approaches, the mountain ash tree leaves change their color to orange, and when fall starts, the leaves are purple and red-hued, which is a beautiful contrast to their butter-yellow berries.

4. Sorbus Cashmiriana:- Also called the Kashmir rowan, it is a vast spreading but small deciduous shrub or tree that grows between six and eight meters. Its pinkish white flowers appear in the spring.

They are popular amongst the bees. Over time, the flowers change to pearl-shaped white berries. Its leaves comprise 19 oblong leaflets. It is one of the more beautiful types of mountain ash trees that people grow for its white fruit clusters.

5. Sorbus sargentiana:-It is another beautiful ornamental plant. Native to southwestern Sichuan and northern Yunnan in China, Sorbus Sargentiana is a mid-sized deciduous plant. It belongs to the Rosaceae family and yields white flowers, which change to red berry clusters. Its leaves change their color to orange-red in the fall. The the mountain ash tree plant thrives at an altitude between 2,000 and 3,200 meters.

6. Sorbus commixta:- ‘Embley’ or the Japanese Rowan is native to Japan. But, you can also spot this mid-sized, upright plant on the Korean island of Ulleungdo and Sakhalin (in the Russian Far East). Commixta implies mingled or mixed, which is how it gets its name. The plant has creamy-white flowers that change to deep red fruits. In the fall season, its leaves turn orange and bright red.

Frequently Asked Questions

Ques 1. How long does it take for mountain ash to mature?

Ans. Typically, mountain ash lives for at least four centuries. It takes about two to three decades to reach maturity.

Ques 2. How tall do mountain ash trees grow?

Ans. Usually, mountain ash grows to 33 feet, but the height depends on the variety and species. At maturity, it has a vast spread of 15 feet.

Ques 3. Are mountain ash trees fast growing?

Ans. Mountain ash tree growth rate is slow. Its height increases at less than 12″ per year.

Ques 4. Are there any dwarf mountain ash trees?

Ans. There are several dwarf mountain ash trees. The Dwarf Mountain Ash Sorbus reducta is one such variety.

Ques 5. Are mountain ash trees invasive?

Ans. The European Mountain Ash Tree can be invasive. It naturalizes fast and propagates readily. In seven states, it is invasive, where it shouldered native shrubs and escaped cultivation.

Ques 6. Mountain ash tree berries – Are they edible?

Ans. Though edible, mountain ash berries are not very tasty. Also, eating them in large quantities may be unsafe.

Ques 7. What is mountain ash used for?

Ans. The Mountain Ash tree is used for:

People use mountain ash berries to make medicine. It may be dried, cooked, or used fresh.
The plant helps with heart diseases, gout, diarrhea, and several other conditions.
Mountain ash is a popular ingredient in stewed fruit, marmalade, vinegar, juice, tea mixtures, and liqueur.
Berries contain Vitamin C and can help reduce inflammation.
Some even use the Mountain ash as a remedy against kidney diseases, arthritis, blood purification, menstrual concerns, and lung conditions.

Ques 8. What is the difference between American mountain ash and European mountain ash?

Ans. American Mountain Ash is a beautiful, mid-sized plant. It blooms in late spring with spectacular white flowers that appear in clusters. It is a perfect specimen for the ornamental tree in a residential setting.

Their decorative orange berries stay attached to the trees across winters and are a delight for the birds and wildlife. They grow to 10 meters with a six-meter spread. They need full sun to thrive. Their fall color is scarlet-red. The American Mountain Ash has a high pollution tolerance. These types of mountain ash trees have a medium growth rate.

Similarly, European Mountain is a beautiful, mid-sized ornamental tree that yields white-yellow flowers during spring. In the summers, the flowers become small orange and red berries. The berries are bitter and are used for making the Rowan Jelly.

It also attracts birds in a residential setting. The European Mountain Ash has reddish-brown buds. They are densely hairy, not sticky, and full of gray hair. On average, they have a height of 15 meters with a spread of five meters.

They thrive in partial shade or full sun, and their fall color is orange-red. The European Mountain Ash has a medium pollution tolerance and a fast growth rate.

Conclusion

So, this brings us to the end of our Sorbus mountain ash trees’ guide. With this guide, you must have a better understanding of their growing tips, uses, and more. We are sure you will be able to spot mountain ash when you come across it.