Autumn = Planting time of trees
– auf Deutsch lesen – “Wood” is our theme this autumn at the Garden Academy, and follows on from the summer dedicated to the Rose. We have chosen this subject to highlight the importance of woodlands and the valuable role trees play in our lives. At a time where precious woodland habitats are increasingly threatened and trees struggle with drought, heat and various pest and disease problems, it is high time we take a new approach to these vital plants, without which mankind would not survive.
Trees struggling for survival
Travelling through Germany these past few summers, I have noticed numerous woods with dead or dying trees. We watched elms disappear out of our landscapes, now various other great trees are endangered, like ash and horse chestnut and beech woods are struggling for survival. Within urban spaces the situation is not much better. Only small selection of tree species is commonly planted as urban street tree. Many of these have disease problems, often as a result of the stress caused by the lack of water and hot summer temperatures.
It’s planting time – diversity of species
Admittedly, a few garden trees will not replace dying forests, but they will help on a small scale. Knowing what to plant is the tricky aspect. Many ecologists say we should plant native species, as these are of greatest benefit to our native wildlife. The problem with this is that the climatic changes also adversely affect native species. However, several studies have shown that in many cases, insects are proving to be more adaptable than expected. That some insects which relied on a particular native tree, have adapted themselves to another related species of the same genus.
Southern European trees
Based on my personal observations these past few years, I have decided that increased diversity is the safest bet. We should not ignore our natives, but we need to look at trees that originate in drier climates, hat will cope with long, hot, rain-less summers. Oaks from southern Europe, such as Quercus cerris is for example an interesting candidate. Some long-naturalised groups occur in Germany of this handsome genus with its furry new shoots, probably introduced by the Romans.
North American trees
Several tree species that originate in north-American have proven to be well-adapted to our new climate.
Juglans nigra, the Black Walnut is a fast-growing tree, that will become tall and slender when surrounded by other trees, otherwise they will make a wide crown. Although darker, the nuts are very similar to our familiar walnuts, but richer in (healthy!) fatty acids and superior in taste. As it will not keep for very long, it is sadly rarely offered for sale.
Liquidambar stiracyiflua is much loved by many gardeners for its sensational autumn colour, but it also makes a useful street tree. With age it will develop a deeply ridged, characterful bark which I find very attractive. In America the timber is highly valued because of its high quality.
Nyssa sylvatica makes an attractive solitaire specimen and is one of the most spectacular trees for autumn colour. Even when young they already make an impressive show. In spring the new foliage also has a reddish colour. In North America it is a very popular wildlife tree. Birds and small mammals love the acidic fruits that are produced in autumn, bees love the nutrient-rich nectar.
Catalpa bignonioides is another North American tree that has great garden value. It is late coming into leaf, and drops them early, making them valuable as summer shade trees, allowing plenty of light through at times of year when it is appreciated. In spring time it is wonderful to catch early rays of sunshine, in July one tries to hide from them. Its large leaves are very architectural, and the big heads of white flowers very decorative in summer. By late summer the flowers have made way for its characteristic long bean-like pods. Its late flowering habit means the tree can be pruned and kept compact, and yet still produce flower that season as they come on new growth.
From the East
In contrast to the above, Zelkova serrata is a tree that originates in the east: Japan, parts of China, Taiwan and Korea. It has similar characteristics to our elm trees and will turn into mighty, impressive trees with age, though it is slow growing. It has an interesting patterned bark, which peels to reveal small patches of different colours. In Japan it is a tree which is highly revered, similarly to ginkgo trees, and much used in the manufacture of furniture. When planted as a solitaire, it will form a much branched, wide crown. Its leaves are attractively serrated, and remind a little of our beeches, though narrower and on more slender stalks.
Trees with tradition: Mulberries
One particular tree for which I have always had a great fondness is the mulberry. The White Mulberry has always been popular, and was traditionally planted for the silk industry. The caterpillars whose cocoons are used to produce silk feed on the leaves of Morus alba. In southern Europe this tree is often used as a street tree, where it is often pruned back hard during winter. The strong new shoots will provide much appreciated shade during summer, but will not flower or produce fruit. The white, blackberry-like fruits can often be bought from dried fruit specialists.
In many old gardens in England, you can always find a black mulberry: Morus nigra. Already at a young age they can look old and gnarled. When left to grow uncut, their crown develops quite low above the ground, making it easy to harvest the fruits from the gnarled branches. These are my all-time favourites. You have to wait until they are very dark-purply black colour. Then they are deliciously rips. Their flavour is unique. The only draw-back is that they are very easily bruised, so you can never pick them unnoticed: your hands (and usually also your clothes) will be stained by the delicious juices. It makes the fruit also completely unsuited for any commercial purpose, as it is impossible to transport or store them. You can just about carry enough to the kitchen to serve with meringues and cream. Originating from the near-east, there is a long tradition of growing them in our gardens.
Both mulberries are reputed to be frost sensitive, though until now, I have never known them to suffer much damage, other than the occasional knock back by a late frost.
Benefits of trees
Many garden owners are reluctant to plant a tree, as they worry about shade, leaves and root competition. But think how wonderful it was during the height of summer to sit in the cool shade of a tree canopy; how the mass of foliage absorbs noise from the neighbourhood; captures dust from the road; screens you from the outside world and provides a home for so many birds, insects and small mammals. Hearing lime trees hum with the activity of bees, watching squirrels forage for nuts or blackbirds fight over the ownership of a berry-laden tree is a delight. All that goes on whilst in the background, these green giants quietly get on with their task of absorbing and fixing carbon out of the air, and producing fresh oxygen for us to breathe.
Your planting time – do something for your landscape!
You, as garden owner, cannot do much to green the rural landscape or the urban streetscape, but you can make a contribution to your local landscape and to the environment by planting trees – at least one. Where space permits, try to plant a proper tree, one that will develop into a medium or large size, which as it grows, will become a noticeable part of the local scenery. We benefit from the trees planted by our predecessors. Think ahead of generations to come, and think of the joy they will have at the tree you planted.
Now is the time to plant: they will be able to settle in and install themselves before the start of winter, and make them better prepared to face the challenges of next season!Leave a comment