Mountain ash (rowan in British English) is an elegant shrubby tree that both bees and birds adore. Spring blooming is full of nectar and turn into nutritious red berries by Fall for birds.
| Name | Sorbus aucuparia |
|---|---|
| Family | Rosaceae |
| Type | tree |
| Height | 16 to 50 feet (5 to 15 meters) |
| Exposure | full sun |
| Soil | rich and deep, not very chalky |
| Foliage | deciduous |
| Flowering | late spring to early summer |
| Fruit formation | early summer to mid-autumn |
A very easy tree to care for, it’s perfect for wild hedges along large fields, shrub beds, and even occasionally as a standalone.
Favor planting in Fall to make it easier for the plant to spread its roots and properly resume growth in Spring. For plants purchased in pots or containers, you can plant in other seasons than fall as long as both freezing and dry spells are avoided.
Sorbus has quite a long lifespan, reaching to over 120 years old.
No pruning mandatory, but if you wish to reduce or reshape the shrub, wait for the blooming to end. Winter is also a good time (at the end of the season).
However, what’s very important is never to prune between early spring 15th and midsummer 31st. In many countries, the law forbids it with good reason, since this is when wild birds are nesting.
Each job on a rowan has its own window, and one of them is a legal one. Use this table to see at a glance when to act and why.
| Task | When | Why then |
|---|---|---|
| Planting bare-root | Autumn | Roots settle over winter and growth restarts well in spring |
| Planting pot-grown | Any season, outside frost and drought | Container roots are undisturbed, so timing is flexible |
| Reshaping or reducing | Once flowering has finished, or late winter | Pruning is optional and the tree is not in full growth |
| No pruning at all | early spring 15th to midsummer 31st | Wild birds are nesting; in many countries the law forbids it |
| Harvesting berries | Autumn | Fruits are ripe and ready for jam, jelly or spirits |
Thinning dead wood from the centre at pruning time also lets light in and boosts the following crop.
Beyond the wild species, nurseries offer named rowans that differ mainly in berry colour, shape of the crown and cut of the leaf. The table below compares the ones most often sold, so you can match the tree to the space and to the use you have in mind.
| Variety | Berry colour | Habit | Foliage interest | Best for |
|---|---|---|---|---|
| Black Hawk | Orange-red, large | Broadly columnar | Thick, dark green leaves | Exposed, windier sites |
| Rossica Major | Bright red, large | Tall, strong-growing | Big, healthy leaflets | Heavy crops for kitchen use |
| Autumn Spire | Yellow | Narrowly columnar | Red-purple autumn colour | Narrow gardens and avenues |
| Sheerwater Seedling | Orange-red | Narrow, upright oval | Standard ferny pinnate leaves | Streets, drives and small gardens |
| Cardinal Royal | Bright scarlet | Upright oval | Dark green, silvery beneath | North American street planting |
| Fastigiata | Deep red, large | Columnar, very narrow | Stiff, dark green leaflets | Tight spaces and narrow borders |
| Asplenifolia | Red | Medium, rounded crown | Deeply cut, fern-like leaves | Specimen tree with light shade |
| Beissneri | Orange-red | Upright, fairly narrow | Cut leaves, coral-red bark | Winter bark interest |
| Xanthocarpa | Amber-yellow | Medium, rounded crown | Typical pinnate foliage | Yellow-berried contrast for birds |
| Fructu Luteo | Golden yellow | Medium, open crown | Green leaves, good autumn tint | Gardens wanting non-red fruit |
| Edulis | Red, large fruits | Medium to tall, vigorous | Broad leaflets | Jam, jelly and spirits |
| Moravica | Red, mild-tasting | Medium, upright | Sparsely toothed leaflets | Edible berries, less bitter |
| Pendula | Red | Weeping, low and spreading | Arching, drooping shoots | Lawn feature or small plot |
| Dirkenii | Orange-red | Small to medium, rounded | Golden-yellow young foliage | Bright foliage accent |
A common name for this tree is “bird ash tree”. Our feathered friends favor it for the many red-orange berries that hand to the tree even as leaves have fallen away in Autumn. Excellent to attract birds to your garden. They’ll thank you with a chorus of birdsong all summer long!
In Spring, you’ll also find the tree buzzing with activity. It’s one of the main suppliers of nectar for insects and honeybees. Helping the environment out on all accounts!
Rowan mountain ash used to be planted along fields to attract thrushes in Autumn for hunting. Fruits, or rowanberries, are edible even when raw, though they taste too rough and tart, not a very pleasing experience. They’re excellent when baked into jam and jelly.
You would harvest the berries in Fall. There are many varieties of rowan tree, most bear red berries, but there are a few ornamental yellow-fruited ones, too. Birds, however, love them all!
So whether raw or cooked, mountain ash berries are edible. Nonetheless, it’s strongly recommended to only nibble on a few at a time. When ingested raw in greater quantities, a slightly toxic side-effect appears which is due to parasorbic acid (literally “the acid of the Sorbus tree”), a compound present in the berries. Cooking produces heat that breaks this particular parasorbic acid down, so it disappears. This makes it possible to cook jelly, jam, and even spirits or alcohol from the fruits of these mountain ash berries.
Boost flower and fruit formation easily by removing dead wood from the center of the tree. Branches often die naturally as months flow by, and cutting them off frees space for light and sun to enter.
