The skeleton of birches in winter, with their ghostly white trunks and bony branches, are enhanced by blood-red dogwood planted beneath, writes FIONNUALA FALLON
It was only a few years ago, when I first saw the densely planted, double avenue of silver birch that frames the main plaza leading to the Tate Modern in London, that I finally fully appreciated the stark, bare-boned beauty of the winter garden. Set against the austere backdrop of the former Bankside power station, framed by a wintry, starry sky, and up-lit so that their ghostly white trunks and pale branches gleamed in the twilight, those trees made an unforgettable impression.
The birch tree that Irish gardeners know best is probably the Himalayan birch, ‘Betula utilis var. jacquesmontii’ – a mouthful of a Latin name but a beautiful tree with an elegant growth habit and whitewashed trunk and branches.
There are other, equally beautiful if less well-known birch species that also make fine specimen trees. This year’s Bloom garden show, for example, featured a gold-medal winning town garden designed by landscape architects Patricia Tyrrell and Deirdre Prince, in which pride of place went to a multi-stemmed golden birch (Betula costata, supplied by Cork nursery Nangle Niesen) whose peeling, papery limbs I wanted to reach out and stroke. A quick-growing tree, this birch will eventually reach a height of 10-15m.
Other garden-worthy species of Betula, which have decorative barks and branches, include the shaggy-barked river birch, Betula nigra and the Chinese red birch, Betula albosinensis ‘Fascination’, which sports a tawny-coloured, flaking trunk and cinnamon-coloured branches.
At this time of the year the spare, pared-back beauty of any birch tree looks especially lovely when underplanted with other colourful winter twiggery, such as the shrubby, ornamental dogwoods. Olive-green Cornus ‘Stolonifera’, bright scarlet Cornus alba ‘Sibirica’ or C. ‘Baton Rouge’, purple-black C. alba ‘Kesselringii’ or the more compact, less vigorous C. ‘Midwinter Fire’ can all be used successfully this way, especially when planted en-masse.
Hardy and tolerant of a wide range of growing conditions, they do best in damp soils and full sun and benefit from a hard pruning in spring.
Those same dogwoods also look impressive when planted next to the prickly purple-silver stems of the ghost bramble, Rubus thibetanus ‘Silver Fern’, a medium-sized deciduous shrub whose strangely luminous beauty only comes to light in winter once it has shed its leaves. Its larger cousin, Rubus biflorus, produces similarly arching, silver-white stems.
Voted the best of all the white-stemmed Rubus by the RHS, this plant reaches a height and spread of 3-4 metres, making it suitable only for larger gardens. But if you do have the space to grow it, try underplanting it with sheets of snowdrops, whose icy prettiness will echo the Rubus’ silver-white tones.
Another group of plants greatly valued for their colourful winter stems are the willows. Salix alba var. vitellina ‘Britzensis’, more commonly known as the coral bark willow, will make a largish tree up to 25m tall if left to its own devices.
Regularly pruned, however, it can be treated as a medium-sized shrub (about 2m tall). Annual coppicing (where the stems are cut back to ground level) results in a multi-stemmed shrub and encourages the plant to produce lots of its gorgeously fiery, orange-red branches. Useful as a handsome, fast-growing screen or hedge, those colourful stems are also valued by flower arrangers, basket makers and for use in living willow sculptures. Its close relative Salix alba ‘Yelverton’ produces even redder stems, Salix alba ‘Hutchinson Yellow’ produces bright yellow stems or “wands”, while Salix daphnoides is known for its purplish-brown stems.
Mass-planted, these willows look spectacular when backlit by low rays of winter sun and associate well with the aforementioned shrubby dogwoods and rubus.
If its ornamental catkins you’re after, look out for the black willow (Salix gracilistyla ‘Melanostachys’) or the Kilmarnock willow tree (Salix caprea ‘Kilmarnock’) while flower arrangers have long loved the curling, coiling growth of the contorted willow, Salix erythroflexuosa. Just like the shrubby dogwoods, plants in this group are known for their hardiness and do best in a fertile, moist soil and either sun or light shade.
Finally, there’s the coral-bark maple, Acer palmatum ‘Sango-kaku’ – a small tree for all seasons, prized not only for its gloriously colourful, deeply cut foliage but also for its coral-pink young branches that light up the winter garden.
Slow-growing, fully hardy, but with a preference for dappled shade, shelter from strong winds and a moist but well-drained soil (neutral to acid), it will reach an eventual height and spread of roughly 6m.
If you put this tree in a prominent position in the garden, its winter finery can be fully appreciated. Stars like this should be allowed to twinkle brightly.
Artist Sonia Caldwell's garden calendar for 2013 features her wonderfully detailed water colour illustrations of fruit, herb and vegetables and would make a handsome, affordable present for gardeners(€12.50 including p&p, see illustratedirishprints.com)
