DOG days in August leave me impatient for change, but convention creates a conundrum because two different days in September are used to mark the first day of autumn. One is governed by the Earth’s axis and orbit around the sun, while the other is one of the milestones in four three-month seasons created to be compatible with our Gregorian calendar. The dawn of a meteorological autumn is 1 September and 22 or 23 September for an astronomical autumn.

READ MORE: Saman tree is not all it appears

An extra 20-something days at a time of dynamic change makes a world of difference to trees and woodland. According to the astronomical calendar, the first 21 or 22 days of the month are still within summer – a feeling I can chime with when a string of hot sunny days in August extends into September, although the summer season is already closing down. 

Forestry Journal: Dog rose hips seen here in September 2019. Colouring up nicely but not yet sufficiently soft for birds and small mammals.Dog rose hips seen here in September 2019. Colouring up nicely but not yet sufficiently soft for birds and small mammals.

By 21 September, 2021 (autumn equinox), the day’s length will have decreased by four hours and 21 minutes in relation to midsummer’s day (21 June), while other astronomical changes weaken rays from the sun, now lower in the sky. A consequence for deciduous trees is the breakdown of leaf chemicals into soluble components which can be ferried for storage in the trunk, branches and roots before senescence culminates in abscission and leaf fall. 

These related changes in sunlight and leaf canopies are signalled throughout September to provide a fascinating experience for the keen-eyed observer. First to document September’s interacting light and leaf colour phenomena was none other than William Wordsworth (1770–1850) in his iconic poem ‘September 1819’:

Departing summer hath assumed,
An aspect tenderly illumed,
The gentlest look of spring;
That calls from yonder leafy shade,
Unfaded, yet prepared to fade,
A timely carolling.

Wordsworth describes September sunshine comparable in strength and angle to April’s, and its illumination of chlorophyll-depleted leaf canopies to display the more ‘pastel’ shades of green associated with spring. This visual conundrum is all the more authentic in hedgerow trees bordering newly ploughed fields ready for autumn sowing.

Forestry Journal: Sloes in September, blue with a buff surface covering but not ripe for use by man or beast until the first frosts of late autumn.Sloes in September, blue with a buff surface covering but not ripe for use by man or beast until the first frosts of late autumn.

Where did summer go? Seasonal spoils are borne on the hedgerow as ripe fruits and extension growth which can be phenomenal considering we are in a cool–temperate climate. The fastest growers, like common elder and hawthorn, will have at least two feet (60 cm) of growth under the belt, while even the slower ones such as blackthorn and field maple will have put on a full foot (30 cm). 

September is when fruits of the season hone the colour changes which began in July. Dense clusters of rowan berries will have developed their final vivid-orange colour, while juicy berries on common elder are black and sufficiently ripe for berry-eating birds. Haws that hang from hawthorn trees are bright red but not yet of the deep and dull shade which tells they are ripe.

Spherical sloes on blackthorn bushes are full and blue with a waxy bloom but still weeks away from the frosts that will soften and sweeten these plum-like berries for use by man and beast. Holly berries are colouring up but not yet of the crimson-red prized for Yuletide, and not sufficiently sweet for birds until the New Year dawns. Blackish berries on common ivy are not yet born, because September is the month when this out-of-synch native starts to flower. One of the strangest sights in September is red hawthorn berries and ivy flowers side-by-side in the hedgerow.

Forestry Journal: September is when the out-of-synch common ivy decides to flower. Seen here in the hedgerow with reddening leaves of dogwood hanging on to the last of its black berries.September is when the out-of-synch common ivy decides to flower. Seen here in the hedgerow with reddening leaves of dogwood hanging on to the last of its black berries.

Writers have waxed lyrical about autumn as a season of abrupt change. Sadness at summer’s demise and the crisp, clean sunlight which lights up a changing landscape seems significant in September’s superiority. Robert Bridges summed up September as ‘fading flowers and ripening fruits bathed in soft sunlight’:

Earth’s flaunting flower of passion fadeth, fair,
To ripening fruit in sunlit veils of the air...

From ‘The Months’ (‘Basil and Edward’)
By Robert Bridges (1844–1930)

Light was apparently a key factor for William Wordsworth when he wrote ‘Composed upon Westminster Bridge, September 3, 1802’:

This City now doth, like a garment, wear,
The beauty of the morning; silent, bare,
Ships, towers, domes, theatres, and temples lie
Open unto the fields, and to the sky.
All bright and glittering in the smokeless air,
Never did sun more beautifully steep,
In his first splendour, valley, rock, or hill.

The Thames riverfront at that time was built up, but the hinterland stretching out south of Westminster Bridge was still a network of rural villages. This would have presented Wordsworth, who was sitting on top of a horse-drawn carriage, with a contrasting view of buildings, ships and docks in the foreground, and fields, hedgerows, trees and woodland stretching out beyond.

Forestry Journal:

September was traditional harvest time, which comes across strongly in the poetry of past centuries. L.M. (Lucy Maud) Montgomery highlights this link in her poem ‘September’, and pays tribute to the ‘late delight’ of September with flowering red poppies scattered amongst ripened corn:

Lo! a ripe sheaf of many golden days,
Gleaned by the year in autumn’s harvest ways,
With here and there, blood-tinted as an ember,
Some crimson poppy of a late delight,
Atoning in its splendor for the flight,
Of summer blooms and joys,
This is September.

However, the setting for this poem is not all it seems, with a clue perhaps in the way ‘splendour’ is spelt, and despite the reference to Papaver rhoeas (corn poppy), a European native plant. Lucy Maud Montgomery (1874–1942) was a native of Canada and all evidence suggests she was describing a September scene on Prince Edward Island, where she was born, and where Papaver rhoeas is an alien weed in cornfields.

The traditional link between end of the harvest and end of summer has been well and truly broken after successive changes in agrarian practice. The cereal harvest now starts in July and is done and dusted before the end of August.

Also set in North America with clues to its provenance is a poem with the same title, ‘September’, composed by Helen Hunt Jackson (1830–85):

The golden rod is yellow,
The corn is turning brown,
The trees in apple orchards,
With fruit are bending down,
The sedges flaunt their harvest,
In every meadow nook,
And asters by the brook-side,
Make asters in the brook.

The main clue is in ‘golden rod’, a UK garden plant growing widely on railway embankments but a native of North America. Some years ago I was asked to visit the Royal Forestry Society Library (such that it was), when the RFS was based at Tring in Hertfordshire, to write an article about the collection. At the bottom of a pile of largely inconsequential texts (including, as I recall, a telephone directory) were several apparently authentic copies of John Evelyn’s Sylva, published in the mid-17th century. Inside one was a collection of very old letters including one written in the 1700s by a plant collector in Pennsylvania. He had sent a specimen of a wild herbaceous plant, apparently golden rod, for a colleague in England to identify.

Forestry Journal:

Another clue is in the word ‘aster’, traditionally used in America to describe the pale-blue flowers that we call Michaelmas daisies. Perhaps we should call them ‘asters’ too, because they are native to North America. They were brought here as garden plants but escaped and now flourish anywhere and everywhere, from well-lit margins of woodland to railway embankments. Whatever you choose to call the plant, it is a flower of September, in one instance named after the Feast of St Michael and All Angels or Michaelmas, celebrated on 29 September. 

Sometimes you seize upon a September poem expecting the poet to be talking trees, butterflies and flowers, only to find this ninth month of the calendar year in a completely different context. Such is ‘September 1913’ by W.B. Yeats (1865–1939), arguably Ireland’s greatest poet. He mediates not on the geometry of natural light or the colour chemistry of deciduous leaves but the dire political situation in Ireland in 1913, and laments a lost past for his home country:

But let them be, they’re dead and gone,
They’re with O’Leary in the grave.