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We are blessed with two birch trees native to this isle, the silver birch and the downy birch. These are also known by the Latin names of Betula pendula and Betula pubescens, or in Irish, Beith Gheal agus Beith Chlúmhach.
Silver birch
Betula pendula (silver birch), the more upright of our native birches, is also commonly known as white birch. These common names are very appropriate for a tree whose trunk and arching branches are covered with greyish-white bark. Dazzling bark colour such as this is one of the main reasons that the silver birch has become a widely planted garden tree right throughout the country. Imagine for a second a cluster of five silver birches, planted within a large heather bed, which is lightly dusted with snow, a perfect winter scene and one that many avid gardeners long to recreate. Unlike other trees that fade into the background once our leafless winter comes around, the elegant silver birch stands tall and, like Irish backpackers first day on Bondi Beach, proudly displays its bright white chest and arms for all to see.
Covering the delicate looking branches of the silver birch is its foliage, shimmering diamond shaped leaves, toothed on their lower halves. As well as bark colour, the leaves of the birch are good providers of seasonal colour, green for most of the year, with a welcome vibrant flush of yellow colour before shedding in late autumn.
Because of the light and dispersed nature of these leaves, silver birch allows a fair quantity of filtered sunlight to brighten the ground beneath. This allows us to under-plant the tree if desired (heathers anyone). The flower of the silver birch is a nondescript catkin, a dangling cylindrical bloom that is followed afterwards by winged seeds.
Downy birch
Betula Pubescens (downy birch) is the second of our native birches. This tree is very similar to the silver birch except that for a few telltale differences. Firstly, its bark is a creamy brown in colour. Downy Birch branches also tend to display a slightly pendulous habit compared to the more ascending branches of the silver birch. However, the most telling difference between the two is the fine downy fur that coats the new twigs of Betula Pubescens, hence the common name.
Growing the birch
Both birches can be found growing wild throughout the bogs of Ireland, these locations giving us some clues as to the tree's growing requirements. Although preferring a free draining soil, our birches will grow quite happily in peaty or boggy soil. This is because they are quite shallow rooted, so don't forget to water them deeply during dry weather. The birch is also quite resistant to cold winds, which can often be found gusting across an open bog.
Along with being beautiful garden trees, there is one more 'green' reason I will offer you for planting a native birch. It is estimated that a single mature silver birch growing to 13 metres (40ft) high, can support up to 229 different species of insect. This is equivalent to a virtual city within a single tree. That point alone is a good enough reason to bring back the birch.
Until next week, happy gardening and remember that a weed is just a plant in the wrong place.
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