Now and Then: February

When Margaret Nettlefold planned the garden at Winterbourne, daughter Valerie revealed that her mother ‘lived with gardening books for a year or so’. Here, the influence of Gertrude Jekyll is inescapable. Winterbourne is filled with Jekyllian detail inspired by her 1899 classic Wood and Garden. Each month, we follow in Margaret’s footsteps to see how the garden compares now and then…

“In summer-time one never really knows how beautiful are the forms of the deciduous trees. It is only in winter, when they are bare of leaves, that one can fully enjoy their splendid structure and design, their admirable qualities of duly apportioned strength and grace of poise…” Gertrude Jekyll, Wood and Garden, 1899

It is true that one of the great pleasures of winter is the sight of a deciduous tree in silhouette. Without leaves, even the smallest of branches can be seen forming a fine tracery of lines that can be followed all the way to the trunk. But no two trees are the same; their leafless outlines reveal many different shapes and habits that might otherwise be missed, hidden behind foliage in the summer.

Black gum in the Sunken Garden, photograph by Maggie Bucknall

Consider the rounded habit of the black gum (Nyssa sylvatica) in the Sunken Garden in contrast with the conical crowns of the conifers on the Old Arboretum Lawn. Or upright yews (Taxus baccata ‘Fastigiata’) with corkscrew hazels (Croylus avellana ‘Contorta’) and weeping forms of willow (Salix babylonica), birch (Betula pendula ‘Youngii’) and larch (Larix kaempferi ‘Pendula’).

Some of these differing shapes and forms occur naturally. Others have been cultivated deliberately by plant breeders and nurserymen to increase their ornamental value, but all will respond differently depending upon the conditions in which they grow. Each twisted branch or leaning trunk can be read as an arboreal clue revealing something of the natural landscape beyond.

Monkey puzzle tree, Korean fir, and blue Colorado spruce on the Old Arboretum Lawn

Trees that grow against strong winds will be short and squat whilst those in relative shelter might grow tall and thin. For this reason, you will notice that our young trees are staked low to the ground, giving plenty of support, but also allowing them to develop their own natural shape. Trees that are staked too high will grow artificially tall and weak and fall over in the wind once the stake is removed.

 “For nothing in the growth of trees can be much more unlike than the habit of the oak and that of the weeping willow, though the unlikeness only comes from the different adjustment of the same sources of power and the same weights, just as in the movement of wind-blown leaves some flutter and some undulate….” Gertrude Jekyll, Wood and Garden, 1899

In fact, differing weather conditions can impact upon a trees growth in all sorts of different ways. Trees of the same species grown closely together will sometimes taper to a point with the shortest trees indicating the windward side of the group. This is called the ‘wedge effect’.

The ‘wedge effect’, beech trees in Edgbaston Wood, photograph by Eleanor Hill

Here, the prevailing wind comes from the south-west. A quick glance at the skyline may help you navigate your way around Winterbourne. However, more often than not, we grow lots of different species side by side, hailing from all four corners of the earth, and each responds differently to life in the suburbs of Birmingham.

Grown together in artificial communities, these trees do not relate to each other as they would in the wild. Our giant wellingtonia (Sequoiadendron giganteum) planted in the North American section of the Geographical Beds will soon tower above nearly everything else in the garden and yet it was only planted in 1985. Perhaps then, unrelated species should be examined for clues in isolation instead.

The ‘tick effect’, Betula pendula ‘Youngii’ on the Arboretum Lawn

Grown in open ground, a solitary tree will often grow more on one side than the other. On the southern side, where the sun is strongest,  branches will tend towards horizontal, but on the north side, branches are pulled vertically in search of light, shifting the trees weight disproportionately from north to south. This is called the ‘tick effect’ and occurs as the whole tree is drawn toward the sun.

 “The snow still falling loaded them more and more; then came the fatal wind, and all through that night we heard the breaking trees. When morning came there were eighteen inches of snow on the ground, and all the trees that could be seen, mostly Scotch fir, seemed to be completely wrecked.” Gertrude Jekyll, Wood and Garden, 1899

These trees are not only sculpted by the weather, but by millions of years of evolutionary pressure as well. The Brewer’s spruce (Picea breweriana) is prized for its graceful outline with pendulous branches that sweep to the ground and long, drooping foliage. A slow growing conifer, it is a native of high altitudes on the western coast of North America and has evolved this cascading habitat as a means of shedding snow.

Brewer’s spruce on the Stream Lawn

But not all of our trees are so well adapted. Heavy snow last December left many of our trees creaking and groaning beneath its weight. A Mediterranean strawberry tree (Arbutus unedo), planted on the Arboretum Lawn, fared the worst; a major limb was torn from its trunk and at such an angle that the subsequent wound cannot be repaired.

Bushy trees like this are the most vulnerable as snow collects in the open crown. Thankfully, very young trees can often be protected from damage. Heavy snow is easily dislodged with a firm shake of the trunk (although you are likely to get covered yourself!) and open crowns can be temporarily tied together with something soft like a pair of old tights.

Snow damaged strawberry tree on the Arboretum Lawn

In February thoughts begin to turn to the spring ahead, and the deciduous trees will soon be clothed again in leaf, but there’s still time to catch a glimpse before the winter ends. Approach each of our trees in an analytical frame of mind and much can be learnt about the garden in winter. Discover which way the wind blows, where the sun sets and the snow falls, with little more than a keen eye and just a bit of local knowledge.

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