While the hot colours of summer gardens are still in their prime, a subtle but profound change is beginning across the London landscape. This is the month when the first whispers of autumn can be heard. Look closely and you will see the horse chestnuts begin to brown, the first flecks of gold dapple the birches, and a blush of red touch the maples. This quiet transformation, driven by the fading of summer's deep green chlorophyll, reveals the spectacular colours lying in wait beneath. It’s a slow, beautiful farewell to the peak of summer and a glimpse of the spectacle to come.
Return on August 13th to discover the first signs of autumn colour.
Article
Colours
Although we may appreciate brighter coloured birds and butterflies in August and enjoy the ‘hot’ colours of a late summer garden, it is the changes in trees that are now starting to have the greatest visual impact. The very first hints of autumn colour may have been noticed last month with horse chestnuts browning slightly, ashes beginning to yellow and silver maples producing the first reds. There may also have been some dappling among the birches and hawthorns as well as the veins on cherry leaves suddenly changing colour.
It is usually around mid August when the first distinct changes give us a glimpse of the great colour spectacle yet to come. If the summer has been a dry one, the leaf loss from stressed trees results in dead leaves starting to congregate beneath individual trees. In some cases entire branches may be shed and in some conifers just one single limb dies, leaving the rest looking quite healthy. The leaves of the horse chestnut, which were among the first to unfold in the spring, are now the first to shrivel. The honey locust gets noticed as it is so quick to turn from green to a shiny turmeric yellow.
The cause of all these colour changes is due to the ubiquitous green pigment chlorophyll, which is now starting to be reduced or destroyed in leaves, resulting in more underlying red and yellow pigments appearing. Even so, there is still a great range of greens across the landscape, varying widely from emerald and lichen green to cucumber and olive. As sunlight is the underlying cause of all these changes, the best colours are often seen in more open situations where the sun has been allowed to do its work on all sides of the tree. In the shade the colour transformation may not even be completed, which means less of a show. Trees rich in sugars such as sweet gums and sugar maples are well known for putting on better shows.
Towards the end of the month more reds start to appear, especially in sumacs, cherries and maples. Birches, apples, acacias and some poplars are also now becoming more dappled. Plane trees and whitebeams may still look outwardly the same but have many more yellow leaves beneath the green ones. Oaks, magnolias and most willows tend not to be noticed, as they still remain resolutely green. Two unexpected colour spectacles are well worth seeking out this month. Some heaths are now awash with the different purples of our native heathers and saltmarshes towards the end of the month can suddenly turn purple due to the mass flowering of the sea aster Aster tripolium.
Unfortunately these two habitats have suffered greatly in our area and where pockets of either heath or saltmarsh have survived the colour effect is hardly of any note. However, further out of London on heaths such as Chobham common and saltmarshes such as the one bordering Two tree Island down the estuary the colour spectacles are arguably the best of the whole month.
