Winter

 

Winter Highlights

Westonbirt in winter is a landscape of surprises and subtle gems. Perhaps the greatest change occurs in our deciduous trees whose appearance alters so completely as to demand us to take a new perspective. Gone are the spring flowers, summer lushness and autumn fireworks. Instead textures, patterns and forms so often overlooked come to the fore. In particular some of our smaller shrubs take the opportunity to grab centre stage. Some like the peeling Erman’s birch stand out for their texture while others like the flaming red-barked dogwood around Scots Corner or scarlet willows in the car park shock us with their colour.

Elsewhere colour is provided by an even more unexpected source – for despite our winter weather a surprising number of our trees choose to flower now. For wind-pollinated trees this makes sense as it is generally windier and there is less foliage to hinder their pollen. In particular, hazel with its dangling lemon catkins is conspicuous around Silk Wood throughout January and February. If you look carefully along the twigs you can also find the purple spikes of the female flower awaiting one of the four million pollen grains produced by each male catkin.

However, the most colourful winter display comes from the witch hazels whose spidery yellow flowers reliably bloom in mid-winter regardless of the weather. The best place to enjoy these trees is Savill Glade. Elsewhere, vying for attention is another yellow flowering tree – the cornelian cherry – a good specimen can be seen at Skilling Gate. For colour and scent one should seek the Christmas box, whose spiky white flowers give off a delightful scent around Circular and Main Drives.

 Conifers

Surprisingly only three conifers – the juniper, Scots pine and yew (not strictly a conifer but a close relative) are native to Britain – the rest, so familiar to us have been introduce. With their bold shapes, needle-like foliage and wide ranging aromas they have rightfully become popular ornamental plants. But although they are of interest all year round it is in winter that their sculptural elegance is best appreciated – standing proud against their gaunt deciduous neighbours. Main Drive and Specimen Avenue are two of the best footpaths to explore the diversity of Westonbirt’s conifers – from magnificent American giants such as Douglas fir and Wellingtonia, to the elegant forms of the western red cedar, Deodar and cedar of Lebanon.

Wildlife

Finally, winter is an excellent time to view Westonbirt’s bird life – as our resident bird species are joined by a variety of northern migrants such as fieldfare, redwing, siskins and bramblings. You may even see crossbills as the move from conifer to conifer tweaking out the seeds from cones.

Birches are widespread throughout the Northern Hemisphere and you can not go far without seeing one. They are generally easy to identify to the genus level but because of their promiscuous habit, which creates many hybrids, they can be difficult to identify to a species level. Both male and female flowers appear on the same tree, dioecious, and take the form of catkins. They are represented in the arboretum by 34 different species and many cultivars. Eight of these are the biggest you will find in the UK and some are particularly rare.

Where to start with such a beautiful genus is always difficult. On that point I will start with one of my all time favorite trees within both the arboretum and the genus, Betula ermanii in square 22H, at the end of Mitchell Drive close to Down gate. This is a magnificent specimen and certainly the best of any birch you will see within the arboretum. I am also sure it is by far our oldest birch, as they do not tend to be long lived. In fact I have not seen a better specimen of birch anywhere in the UK, now there’s a challenge! This species is native to East Asia from the Kamchatka peninsula through pacific Russia to Korea and Japan and westward as far as Lake Baikal. The bark, particularly when young is most attractive and the foliage turns a lovely golden yellow in the autumn. Have a look at the way the bark rolls off the large branches above your head, fabulous! This is a particularly important tree in the Westonbirt landscape and one of its offspring is already growing strongly some ten metres away. This tree in time will replace the original plant. If you have time to look at only one tree in the arboretum then this specimen is certainly a good place to start and finish.

Staying on the same continent another favorite of mine is Betula medwediewii from the Caucasus. This tree has quite a large course leaf turning golden yellow in the autumn. The catkins are large for the genus and can be most attractive at certain times of the year. However the one thing that I love about this tree is the ease of identification. Even without seeing the leaves or bark the very particular habit, of branching at nearly ground level and then growing into what can only be described as a medium sized tree of multistemmed habit, makes identification easy. Our largest specimen is some 30ft tall by 30ft across and is found in square 21D. We also have several smaller specimens in other parts of the arboretum.

On a smaller front but moving northwards is Betula nana. This is a delightful little birch but can be quite hard to grow. Native to both northern Europe and North America it grows over large areas often on wet ground. The leaf is small, generally around one centimetre in diameter with rounded teeth, quite unlike any other birch. It does not grow much more than a metre tall but at its best is most attractive. Because of its northern home it often flushes early in our climate and can then be killed by late frosts.   Betula Papyrifera

Many birches are selected for their very beautiful bark, which gives all year round attraction. The following four plants are in my opinion amongst the best. Many birch cultivars have been selected and given specific cultivar status and if a good bark colour is needed then a named cultivar is probably best selected. Betula utilis has probably more named cultivars than any other species. On that basis I will start with this one. In many ways I would describe this as the typical birch, medium sized tree, upright in habit, generally single stemmed, attractive bark and casting a fairly light shade. The leaves also give a good autumn display. In its early years this tree can be a fast grower often reaching five metres in ten years.

Native to the Himalaya and western China it was first introduced from Sikkim in 1849 by Sir Joseph Hooker. The attractive bark can be variable depending on its home range and differs from a nearly black, variety prattii, to the more common silver. Several good examples can be found throughout the arboretum along with many cultivars.

 What to see in the Old Arboretum & Silk Wood

Plant	What's looking good
Paper-bark maple (Acer griseum)	Bark & stems
Birches (Betula)	Bark & stems
Dogwoods (Cornus)	Bark & stems
Hawthorns (Crataegus)	Berries
Mahonia	Flowers
Hollies (Ilex)	Berries
Willows (Salix)	Stem colour
Stuartia	Bark & stems
Viburnum farreri	Flowers

 Here is a list of other plants of interest this month.  

•      Maples - snake-bark and paper-bark,     (Acer)             Bark
•      Willows,                                             (Salix)             Stems
•      Dogwoods,                                         (Cornus)          Stems
•      Witch hazels,                                     (Hamamelis)    Flowers and scent
•      Christmas box,                                   (Sarcococca)   Flowers and scent
•      Mahonias                                                                 Flowers
•      Winter - flowering honeysuckles           (Lonicera)        Flowers and scent
•      Camellia  (Stuartia pseudocamellia and S.monodelpha)Bark