At this time of year, with autumn colours all around us and leaves pooling at our feet, a gardener’s thoughts often turn to trees. Trees add a maturity and a sense of scale to a garden – they are a valuable addition but have to be carefully considered as a mistake can end up costing a fortune in tree removal and stump grinding.
There are a several considerations which can broadly be boiled down to three main areas: size and shape, multi-season interest, flower/foliage power. In the average small to medium garden, size is extremely important. Do make sure when considering which tree to plant that you note carefully the ultimate height and spread. Research which trees can be pollarded or coppiced (ie regularly pruned down either to the stump or a little further up) to maintain size, and which should not be. Hazels for example, including the glorious purple leaved Corylus maxima purpurea can be pruned back hard to keep small, as can all the Elders as well as most fruit trees. Sometimes this pruning is useful to encourage a single stem tree to break into a multi stem, which is particularly beneficial if it is a tree particularly grown for its bark, such as a silver birch. Silver Birch (Betula pendula) can also be planted in a close coppice. If closely planted in a group of 3 or more this will reduce the ultimate height and spread.
In terms of shape, the key factors are whether the tree is a spreading cone, a fastigiate (upright) shape, or weeping. If space is tight, bear in mind that a spreading tree will not only cast a wider shade, but the root run will frequently go as far as the edge of the canopy thus drying out a wider area and making underplanting difficult. Weeping trees add a different tone to the garden and of course do not need any underplanting unless you want to prune the tree to more of a parasol shape. Personal favourites in the fastigiate category include slender single stemmed birches, Amelanchier Obelisk, Liquidamber ‘Slender Silhouette’, and Fagus sylvatica ‘Dawyck’, otherwise known as the upright Beech.
In the weeping tree category, it is hard to go past the weeping silver pear, or less common the weeping Katsura tree which in either the weeping or upright form is known as the ‘Toffee Apple tree’, or Cercidyphullum Japonicum, as it releases the most extraordinary smell of cooking toffee when its leaves turn golden in the autumn.
The next big factor to take into account is seasonality. There are many trees that look good in one season, but decidedly average for the rest of the time. Many flowering cherries fall into this category, and in the smaller garden it is hard to justify their inclusion. Instead there are the multi season stalwarts which offer three bangs for the buck: spring blossom, late summer fruit/berries, and autumn colour. Into this category fall many of the Crataegus/hawthorns, the Sorbus/Rowan trees, the Amelanchiers, and of course many of the fruit trees. These also rate high on the wildlife benefit scale. Less common but stunning are the flowering dogwoods, as many people will have seen in May at Newby Hall which owns the national collection. These are different to the dogwoods grown for stem colour, and some can be very large trees, but they offer beautiful white or pink bracts in early spring, red strawberry-like fruits in summer, and spectacular autumn foliage.
Sometimes a single flowering or winter bark, or autumn colour can be so stunning that it is worth indulging in the display despite its brevity. Beauty can be even more intense when fleeting. Here you will find the Laburnums, the Lilacs, the Wisterias, the Magnolias, the better behaved of the flowering cherries such as Tai-haku, or Shirotae, and of course the Acers and Liquidambers. Even here if you choose varieties carefully you can add longer term interest. For example the Syringa microphylla ‘Superba’ is a repeat flowering lilac that while less spectacular with smaller flowers, has a prettier shape and maintains the scent of the original.
With all trees, don’t fall into the trap of considering them to be completely maintenance free. Every year you should evaluate them for health and shape. Be prepared to crown lift some of the rounded trees to let light in underneath by cutting off some of the lower branches. Where possible cut out dead wood and when initially planted never forget to give them generous applications of water. To encourage wildlife, hang nesting boxes or bird feeders from the boughs.
Above all we should all remember the Greek proverb: ‘ A society grows wise when old men plant trees in whose shade they will never sit.’
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