Autumn Colour explosion
– auf Deutsch lesen – Almost overnight the annual autumn show started. In the past week we have observed our surrounding landscape becoming increasingly colourful from day to day. Even along Berlins’ leafy streets, numerous oaks and acers have reached luminescent shades of orange and red, whilst butter-yellow lime tree leaves confetti litter the pavements. As part of our Wood theme this autumn, I want to write more about some of the finest trees in the spotlight right now.
The time and degree of colouring varies from genus to genus, species to species and from tree to tree. In addition, the season and the location will also influence the overall effect. Some trees are reliable colour explosions, some less so. Some are supposed to be but turn out a disappointment. I had planted a Parrotia persica in my parents’ garden, promising them an annual firework, but at best the tree turned a mediocre yellow, skipping the technicolour range of colours it should display.
Sunshine affects the degree of colouring that reveals itself in the leaf as the green chlorophyll disappears in autumn, but genetic variance also plays a role in seed-raised plants. The four hornbeam obelisks that stand sentinel by the entrance are still deep green. One trained as espalier outside my office, is already completely yellow. Why? They have different genes, one is the normal type, the sentinels are fastigiate forms and are growing in different conditions: one is in a large pot, the others in full ground.
Reliable early colour – providers are always Euonymus and Acers and are the ones that really set the garden Academy aglow now. As part of our Wood-theme this autumn, we have displayed several trees in the central corridor. Everything was still very green in there until a few days ago, when the Snakebark Maple, Acer davidii suddenly turned a glorious yellow. This develops into an exceptionally fine tree with very attractive new shoots in spring, reaching 10 meters.
Outside there are many Japanese maples showing the huge variation their foliage can attain. They are all particularly suited for the smaller garden, their elegant habit making them ideal trees to create a focal point. The feathery foliage of Acer palmatum ‘Dissectum‘ is just turning a gorgeous orange, whilst the leaves of Acer palmatum ‘Sangokaku’ are coral red, matching the colour of its bark. Acer palmatum Shaina’ is also matching its dark red bark, with glowing deep red leaves. A similar luminous deep red splash comes from Euonymus alatus ‘Compactus’, and even darker red from Cornus alba ‘Sibirica’. But the Japanese maples are not the only ones to provide such a display. In our car park stands a large Acer platanoides. But its autumn colour is particularly fine, which makes me think it could be a particular selection that was planted by our predecessors, but unfortunately there is no label or record of what it could be. Coming down the road, its light beacon draws you in.
I am very fond of the rounded heart-shaped leaves of the Judas trees – they somehow have a pleasing, satisfying appearance with the smooth edges and rounded, generous hearts. The Chinese Judas tree Cercis chinensis ‘Avondale’ is a compacter form which will reach about 2 meters, making it ideal for the smaller garden. It is particularly richly flowering and will do so from an early age. Cercis canadensis ‘Royal White’ requires more space. Usually widely branched, it can reach about 7 meters in height and width, making it also a good focal tree where space allows. The pure white flower clusters also appear before the leaves come. If your garden is large enough to accommodate proper, landscape-changing trees, you should grow Cercidiphyllum japonicum. This large tree with stately upright habit, not only enchants me each autumn with its almost translucent yellow leaves, its very distinctive scent, which can also be smelled in spring, always captivates me. If you find your nose following a mouth-watering smell of candy floss, you know there is one in the vicinity. A beautiful old one growing next door in the university park, has reached the end of its life-span and has been shedding its leaves very early these past few years, but the young one in the Japanese Garden is just doing its bit at the moment and its distinctive scent greeted me as I approached my office this morning. It stands next to the beautiful Prunus yedoensis and opposite an Amelanchier lamarckii which are both glowing orange right now.
Trees – Fruit and leaf
There are several trees that provide a double act: They have good autumn colour with the added bonus of colourful fruits, making them valuable bird-trees. The crab apples may not be renowned for their great autumn colour, but thanks to the contrast with the small red apples, the effect can be eye-catching, like in Malus ‘Adirondack’. This small upright tree is especially useful for small gardens as it flowers opulently in spring. Hawthorns are similarly valuable, especially Crataegus prunifolia. Do not be put off by their black thorns, as it is a wide-crowned tree that will give you much pleasure. Its white flower display in spring is very showy, the bright red fruits in autumn highly attractive and much loved by blackbirds, and the leaves look as if they are on fire right now.
Most of the above described trees are suited to the smaller garden, but some of you may have space for something big, that will be a tree that will provide much pleasure for generations to come. Much to my delight, the local authorities have been planting several Liquidambar styraciflua in the street. Their upright habit makes them look slim and elegant, and it is one of the very best for autumn colour. The leaves will go from green to yellow, and then progress through the entire range of oranges and reds, to finish with deepest purples like a full-bodied delicious red wine. In addition, it is one of the trees that promises to be useful as climate tree, coping with hot, dry summers. Another tough tree is the maidenhair tree. These will develop a lush yellow autumn colour. Ginkgo biloba ‘Obelisk’ is a bushy but slender, columnar form. Another fascinating tree that has just turned yellow is Liriodendron tulipifera, whose soft orange and green tulip-shaped flowers in early summer give it its name: the tulip tree. This will make a large handsome tree, with deeply grooved bark. Its large distinctive leaves have a unique characteristic: the point is missing (apparently, the devil bit it off, as he was jealous of this simply perfect tree!)
Not everybody has the space to plant a large tree, but there are also plenty of smaller ones that may well fit in your garden. It is so important to for us to plant trees. They are beautiful, provide flower, autumn colour and much valued shade on hot summers days. They are our green lung, they absorb noise and dust, they provide habitats for so many organisms that all contribute to the large ecosystem we so heavily rely on. I may be repeating myself, I am sorry to do so, but it is just such an important issue, and now is the best time to look out and plant the next generation that will shape our landscapes.