A tree for all seasons

December 2005

by Gordon Smith

Many trees are more enduring than ourselves, each year going through a cycle of renewal with buds, leaves and often flowers punctuating the passage of the seasons. Each year they increase in stature and influence their immediate surroundings with patterns of light and shade. The change in a single leaf from emergence to falling, multiplied by thousands, creates an image which we come to associate with particular species of tree.

A tree in a garden setting is of more importance than any other plant we are likely to acquire, due to its size and longevity.

Perhaps you have a family event which needs a marker, a new house or garden that needs a prominent specimen around which to plan other planting, or something much more mundane such as screening out some undesirable feature of the adjacent environment.

With Christmas and presents just around the corner, you may be lucky and receive a gift token for plants. Rather than dissipate it on some frivolous winter pansies or spring bedding you might be tempted to achieve something more permanent for your garden, which will remind you often of the donor.

Some weeks ago Ursula Buchan who writes sensibly and knowledgeably about gardening in the Saturday Telegraph did an article on what she considered to be the best 10 trees. Such choices are very personal, tempered hopefully with attention to suitability to circumstances. While I did not disagree with any of her choices, I thought I might compile a list more appropriate to our part of the world.

Here is a set of the ‘best’ trees rather than of ‘favourite’ trees. I have culled an original trial list of 18, with great reluctance and difficulty, to the magic number 10. Each choice needed to have at least one specific virtue, e.g. excellent autumn shape, foliage, flowers, fruit, bark and autumn colour. It seemed reasonable to strike a balance between, for example, deciduous versus evergreen, and native versus exotic. As a working definition a tree should have a single stem at ground level and reach at least 20 feet in height.

Without being too statistical the ratio of the various attributes in my selection has come out as deciduous/evergreen at 7/3; fine autumn colour/generally green 5/5; native/exotic 3/7; flowers/foliage 3/7; special fruiting qualities /none 2/8; special shape/typical tree 5/5 and interesting leaves/ ‘normal’ leaves 5/5. If you were to have all of them then the choice does not appear to be slanted too much in any direction.

If, Desert Island Disc style, you can take only one, then the fun will start. There is no one tree which will have all the most desirable characteristics. If you are strict, then you should still be able to find one for your particular situation. So here, and not in any specific order, is my choice of the 10 best trees for your garden.

Most exotics are inappropriate in rural settings, for example in a lay-by, but are acceptable in a garden setting. Nothing could be more exotic in origin than Cercidiphyllum japonicum, the katsura tree from Japan. Often it may not meet the wish for a single stem at the base, although bought plants come with that initially. The flowers are insignificant, but it scores very highly on its leaves, starting as small pairs of deep purple hearts which progress through summer in a dull, but not drab, green and erupt in autumn into a vibrant display of orange, yellow, red, cream and pink. The final glory is the scent of burnt sugar which is given off on warm autumn days.

Rowans are part of our northern heritage and it is a pity that our native one gets a bit scabby by autumn. For autumn foliar brilliance and attractive fruit one can choose from the large selection of Chinese species and Sorbus ‘Joseph Rock’ gets my vote anytime. The combination of clear yellow berries among bright red leaves wins over the combination of greyish leaves and pink or white fruit of some other species. The inverted cone shape of the branching in Joseph Rock means that it does not cast undue shade.

A tree of similar shape is the flowering cherry ‘Pandora’ with very small flowers which in quantity smother the branches in a pale pink froth. Young leaves are bronze and the falling leaves yellow, orange and red. It may have ‘off’ years for flowering, but generally makes amends the year after.

I tried hard not to have two representatives of the same genus or family, e.g. two birches or two maples, but now I find that I have two cherries. Trees which flower in a spectacular fashion are rare in temperate climates. Laburnum would have made the list, but out of flower it has nothing to recommend it. The double flowered gean, Prunus avium ‘Plena’ has made the list because of its stunning white blossom and its cast iron constitution. The autumn colour is variable and generally not as good as its wild cousins in the countryside.

Frost can be a problem for spring blossom, but it is not a problem for the Chilean Eucryphia. Its open shining white flowers with a boss of brown tipped stamens emerge only in August/September and light up the dark evergreen foliage. This is not a tree for frost pocket gardens as a severe winter will do it a lot of damage, but it is a nice change from hollies. No berries, but the nice tall slightly columnar shape adds to the structure of a garden. Eucryphia ‘Nymansay’ is probably the best to try locally.

Another tree which is remarkably prolific with its flowers is the Norway maple, Acer platanoides, the flowers in this case being bunches of tiny bright lime green stars appearing before the leaves. Not everybody’s idea of flowers, but a tree in spring is a beacon of light, as it is again in autumn with bright yellow leaves, often tinged with red. The sharp points to the leaf lobes make the shape interesting even in green summer mode.

An echo of the colour of the Norway maple flowers can be found in the emerging foliage of beech trees, but unfortunately a beech is too large for the average garden. The solution is to plant the ‘Dawyck’ form which is narrowly fastigiated with all the branches going up vertically. It will still display the same acid green spring leaves and the same orange, brown and yellow in the autumn. It will cast no shade and make an admirable foil to other trees which branch horizontally like Parrotia persica.

The genus Betula includes birches from North America, Europe and Asia and offers some fine bark colours and patterns as well as nice tree shapes. Even so, it is our native birch, B. pendula, which is going to win because of its elegant branching, neat leaves which colour golden and if you are lucky the trunk will have good silvery bark, although not so fine as many Asian species. Of course it is utterly hardy and fits naturally into urban and rural settings.

Conifers can be beautiful trees, but without flowers, no autumn colour for most, generally uninteresting leaf shapes and often no cones except on mature specimens, they must rely on other attributes for inclusion. For sheer elegance, Picea brewerana will get on to the list. From only two small areas of the Siskiyou Mountains on the Oregon/Californian border this is a tree which is worth planting only the very best specimen. This should be a broad based pyramid with a single leader shoot, ascending upper branches which later become horizontal with the lateral branchlets hanging down in vertical fashion forming dark greenish-blue curtains. It is best seen as an isolated specimen, certainly not smothered by other trees or shrubs. Choosing your specimen is rather a gamble as few nurseries have more than one or two plants on offer and it is difficult to judge how a young plant will turn out.

The last of the 10 comes in the form of the third evergreen and second conifer. The Korean fir, Abies koreana, passes the single stem test, although this is hidden by the horizontal tiered branches which begin just above ground level. Given time it will eventually make the 20 foot height. It will cone profusely from an early age and the upright purple cones with streaks of rosset oozing out are always a delight. Like Brewer’s weeping spruce, it should be seen in isolation so that its special shape can be appreciated from all angles.

For that Desert Island experience in the garden I would probably choose the Cercidiphyllum from the list of 10. For the book, either one of Alan Mitchell’s The Gardeners’ Book of Trees or Decorative Trees for Country, Town and Garden. Both now are, I suspect, out of print and would need to be bought second hand.

The luxury could well be the chance to buy that chosen tree at Kirkdale Nurseries, Daviot, Inverurie, who advertise regularly in the Leopard and who have the best selection of trees, and the best advice on trees, in the area.

Dr Gordon Smith began gardening as a small child, helping the flowers to open. After an academic career in botany here and overseas, he is back where he started. Lecturing, travel, food and friends now make for a full life.

This is an article from the December 2005 edition of Leopard Magazine. To read much more like this every month, subscribe to Leopard Magazine.