Trees for Your Farm – Rowan
August 17, 2020
Henry Shaw CAFRE Agri Environment Adviser, Downpatrick
One small useful tree you may have growing on your farm, but perhaps not thought about much, is the hardy rowan (Sorbus aucuparia) or “mountain ash”. Its leaves look like the much bigger Ash tree but this tree is much smaller and can survive well on high ground and damp poor soil.
The Latin name sorbus means “red, reddish-brown” but more poetically, some sources suggest the rowan tree in Irish, is associated with a description meaning “delightful to the eye”. Its complex leaves, delicate flowers in spring and heavy clusters of orange berries at this time of year make this very plausible and an appropriate description. It is a lovely tree to look at, but also one that wildlife depends on.
Mature trees can grow to 15m in height and can live for up to 200 years but most will live for much shorter periods. The bark is smooth and silvery grey, leaf buds are purple and hairy and the large flower clusters, each bearing five creamy-white petals, are white.
Broad leafed tree flowers are often not particularly obvious, but they are always present and often of great help in feeding early insects. Rowan is an exception.
Rowan flowers open early in May – providing nectar for insects before many other sources become available and the tree is a food source for a range of insects including leaf borers, and seven different families of moths.
This time of year the trees are bearing their ripe or ripening fruit. The native rowan bears heavy clusters of orange berries. Many cultivated non-native forms are grown for ornamental use. These have a range of coloured berries (white, purple, red and yellow) that are generally ignored by birds whereas they will feast on the native rowans berries.
The berries are eaten by the blackbird, mistle thrush, redstart, redwing, song thrush, fieldfare and waxwing. Trees are usually stripped very quickly – a sure sign of their nutritional value. A mistle thrush will even defend a rowan tree (or Holly) as its territory, not for nesting in – but for food.
Humans can use them too – the native rowan’s berries, though bitter, are rich in vitamin C and can be made into a jelly to accompany meat.
As a member of the Rosaceae family Rowan is susceptible to a number of diseases such as Fireblight, European mountain ash ringspot-associated virus, and silver leaf disease. These can be introduced through wounds in the bark. Social distancing from a flail hedge cutter is recommended!
The rowan is a beautiful and versatile tree that will grow most places and it is excellent for wildlife. Its compact form makes it a great tree to have on your farm. It is big enough to grow in hedges and its natural beauty will be sure to enhance the view wherever you plant them.
You can grow Rowans from seed – but it takes quite a while as you need to break the seeds natural dormancy. If you plan to grow them gather the berries early – just as they are beginning to colour as germination inhibitors are present in the red pigment. You can macerate the seeds (crush and strip the soft flesh of the berry) and remove the pulp, wash to let dead seed float up, then plant the good seed that collects at the bottom. Alternatively you can plant them whole but they require 18 months “stratification” – over-wintering twice but this method will give the most even germination.