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September leaf fall

Other September pages: Berries, fruits, nuts and seeds • FlowersBirds, insects and animals • Insects, butterflies and animals Weather

Put your cursor over any photo to see its caption, or click here to see more September leaf fall photos.

Leaves do not usually turn colour to any great extent during September: by the end of the month, the treescape is mainly green. Quietly, however, leaf fall has already started. All sorts of trees and bushes are unobtrusively thinning out their leaves, but sometimes the only evidence for this is fallen leaves on the ground. In other cases you may notice tinted leaves - either individual ones or small patches.

Factors that drive this early tinting are varied. Dry summers can definitely sometimes produce it, or possibly how much moisture the tree has had during its entire growing season. Unexpectedly cold nights are almost certainly also a trigger, and possibly also colder than normal weather in general. But part of it does seem to be a general reduction of foliage in preparation for autumn.

Early tinting in September does not generally lead on to more widespread leaf colour, however: it does not mean an early autumn. Any tinted leaves fall and the remaining ones remain green. For this reason strong winds can paradoxically leave the treescape looking less, rather than more, autumnal. It is also quite possible for the month to start with many trees showing a bit of tint and finish with them looking completely green: this happened in 2016, when dry weather in August seems to have been a factor.

(September 2017 was exceptional in that there was quite extensive tint on a wide range of species, probably due to nights of low single digit temperatures on the 1st, 2nd, 9th to 10th, 15th to 17th and 20th to 22nd of the month. But even here the combination of brisk winds and milder nights in the last ten days of the month significantly reduced the amount of colour by the end of the first week of October).

Species which reliably seem to both tint and lose some leaves during the month include crack willow, goat willow, birch, lime, hornbeam and rowan. Alder also sheds foliage but without any obvious tinting and the same is true of poplars (mainly hybrid black poplars, but sometimes also Lombardy poplars), though they may show a very slight yellowing. Weeping willow and white willow can tint very unobtrusively, but mainly shed green leaves.

Shrubs tinting include hawthorn, blackthorn, wild rose and cherry plum, while elder may lose quite a lot of leaves in September without particularly turning colour or while only turning pale green. Some elders and crack willows can be quite bare by the month's end (this was definitely true in 2017).

Brambles also often tint or lose leaves even while they still sport blackberries (or even the occasional flower), and later in the month both dogwood and guelder rose foliage can go maroon even while they still have berries. Forsythia can have attractive maroon tints in its leaves too. Buddleia tints and shed leaves right from the start of the month, even before it is has entirely finished flowering. Both garden and wild privet may also tint a bit.

Other trees which normally keep their leaves till late in the autumn - such as beech, oak, sycamore, sweet chestnut, wild cherry, hazel and field maple - can sometimes produce some tint this month (all did so in September 2017). Ash trees occasionally show some yellowing (this was quite extensive in 2017 and there were lots of leaves shed green), but if you see an ash-like tree aflame with yellow, it is more likely to be a robinia or honey locust, ornamental trees which are quite common in parks and suburban settings. In 2016 and 2017 many ash trees also started to show leaves with blackened shrivelled tips, though I am informed that this is NOT an effect of ash die-back disease. In some years there is also a small amount of shedding from London planes.

In 2009 horse chestnuts also made a fine display of golden leaves in September, but this was a special case. Traditionally the leaves on this tree turned around mid October, but in recent years its leaves have been affected in recent years by a leaf mining bug that causes they to become spotted, and then shrivel. In 2007, 2008, 2010 and 2011 many were shrivelled completely by the end of the month. There were slight signs of hope after the wet summer of 2012, when some trees had reasonable amounts of golden colour towards the end of September, but in 2013 and 2014 after a slow start in July and August the blight increased rapidly in September. This has become the pattern since, though in 2017 quite a few trees were almost entirely shrivelled by the end of August.

Sycamore also has a leaf blight that creates black spots on its leaves (remarkably, this is a sign of clean air), and in 2012 sycamores on the South Downs saw their leaves shrivel early in the summer from an unknown cause, though this has not so far been repeated.

Non-tree or shrub sources of autumn colour in late September include Virginia creeper, a climber found on garden walls and waste ground which turns a glorious red colour as the month goes on, and bracken, which can start to turn in the second half, though this is very variable from place to place. The plants of some flowers can produce colourful foliage as they die back - for example rosebay willowherb, which turns a bright orange colour later in the month, and black bryony, large or hedge bindweed, wood avens and even stinging nettles, which can produce some nice yellows.

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