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Although, in biological terms, bark may be simply a mass of cork and cortex past its sell by date, for gardeners it is 'gift wrapping' that adds beauty and elegance to trees and shrubs. Flowers are fleeting, autumn colour is variable, but bark is a reliable source of pleasure, whatever the season. In winter, when the low sun strikes its surface, the aesthetic value is inestimable. Variations in colour and texture can be astounding. Boles, stems and twigs can be polished, bloomed, winged, spiralled, plated, corked, flaked, striated, or simply satin smooth and temptingly tactile.

Choosing the right trees for your garden depends on various factors, such as aspect and soil conditions. Very damp sites will suit willows, which offer much in the way of bark effect, especially the young growth. Salix alba 'Britzensis' (syn. 'Chermesina') produces orange scarlet stems, while S. x sepulcralis var. chrysocoma has twigs of shining golden yellow. If left, they will both grow to trees with glowing crowns, but are most frequently stooled annually to encourage an array of gleaming, fresh stems. S. daphnoides forms a small tree with young growths overlaid with a white bloom and S. irromta, although of small stature, produces a similar effect. Both respond very well to being stooled.
On drier soils, shrubby dogwoods offer much. The young stems of Cornus stolonifera Tlaviramea' are olive yellow, those of C. alba 'Sibirica' crimson, and those of C. alba 'Kesselringii' black purple. There is even a good selection of our native C. sanguinea, appropriately named 'Winter Beauty', which bears orange yellow shoots that turn red during winter.

These trees are deservedly popular, but the discerning gardener will doubtless search for lesser known subjects. Both Leycesteria formosa and Kerria japonica sport green stems. Rubus cockbumianus has purple stems overlaid with vividly white bloom, as do the equally effective R. biflorus and R. thibetanus. The winged spindle Euonymus alatusRosa roxburghii, when mature, peel and flake in cinnamon tinted hues.
Bark striation is particularly appealing, and is most commonly seen on the stems of some maples. To list them all would read like a catalogue, but some of the best include Acer capillipes, A. davidii, A. grosseri and A. rufinerve. When the various clones and hybrids within this group are added, the choices are quite bewildering. Less obvious subjects with delightfully striated bark are the Mediterranean Genista aetnensis and the Chinese Euonymus bungeanus.

There are many trees which peel or flake dramatically - some horizontally, some vertically and others at random. The bark of the Alpine snow gum Eucalyptus pauciflora ssp. niphophila flakes off in a directionless manner, producing a beautiful effect. The result is jigsaw like, with sharply separated colours ranging from white through grey, olive to deep bottle green.

Arbutus x andrachnoides bark peels back in a spiral or near perpendicular style, giving a colour range from orange through brown to grey. In certain lights, minute shadows are cast against the surface of the trunk from myriad curls of flaking outer bark. This is surely one of the most exciting and unsung beauties of bark - shadow patterns, be they from sunlight filtering down through the tree canopy throwing monochrome leaf shapes across the bole, or from the flakes of exfoliation. The bark of the big shellbark, Carya laciniosa, is shaggy, flaking off randomly in a vertical pattern; when viewed from the ground, and backed by a high canopy of foliage, it is an unforgettable sight.
Almost all stewartias have attractive bark, but the finest, albeit one of the rarest, is Stewartia sinensis. It looks at its best in midwinter when the outer bark flutters away from the bole. One exciting way of magnifying the colour of bark flakes is by siting trees (or shrubs) to catch and filter morning or evening sunlight through them; when seen against the light, the effect is stunning. Warm colours work the best, so choose plants such as Acer griseum, Betula nigra, B. utilis or B. davurica.

Birches are, with few exceptions, out of the top drawer when it comes to bark beauty. North America has given us Betula alleghaniensis (syn. B. luted), with a smooth, lightly peeling bole, and B. lenta with a charming, cherry like, fissured bark. Asia has furnished our gardens with B. albosinensis, as well as its glorious coppery pink variety, B. a. septentrionalis, plus other gems such as B. ermanii and B. costata. The Asian birches frequently exhibit attractive horizontal lenticels (breathing pores), B. utilis, including its variety jacquemontii, being particularly impressive.

Certain rhododendrons flake and peel beautifully. Rhododendron thomsonii varies according to the clone, but one of the loveliest produces fawn coloured flakes set against the grey green, newly exposed bole. R. barbatum is another peeler and at maturity, the limbs have a beautiful polished sheen. Plated barks are also eye catching. The Maritime pine (Pinus pinaster), with its plate faces burnished orange brown, can hardly be bettered.

Parrotia persica is renowned for its autumn colour and its small late winter flowers, but its plated bark, especially on a mature specimen, is a delightful blend of soft and mellow colouration; the same may be said of the bark of the Dutch Elm disease resistant Chinese elm Ulmus parvifolia.

Stooling trees and shrubs creates a multi stemmed effect to maximise the beauty of the bark. It is carried out in early spring, just as the shoots are breaking dormancy. Subjects should be cut back hard (just above the lowest buds visible) on the main stems. This should be done annually on plants such as salix, cornus, rubus and leycesteria, to maintain the attractive colour of the young growths.

Many trees, such as betula, snake bark maples and eucalyptus, respond well to stooling when young. Birches in particular give very good results, as can be seen in the many multi stemmed trees which occur naturally as a result of heathland fire or rabbit and deer damage to seedlings. Some trees don't respond well to stooling, expecially large leaved rhododendrons, such as Rh. thompsonii and Rh. falconeri, but their natural growth pattern usually produces a multi stemmed plant.

Another way to get a multi-stemmed effect is to plant several single stemmed trees in one large planting hole, but this is less successful than stooling. There is also a risk of the trees tearing apart in gales as the central root system will be drastically underveloped, due to competition.

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