In the childhood world of Blackberry-Picking, it is late August. If conditions are ripe, if there is "heavy ran and sun", the "blackberries... ripen". The first bite is addictive, and the children gather containers together and pick blackberries, enough to fill a bath. But they cannot eat them all, and "the fruit ferment[s]". Every year the pattern repeats, they always gather too much.
The poem is divided into two parts, the first longer, describing the gathering of the blackberries, and their consumption, and the second about half that length, the ruin of the remainder. The line length is much greater than in the later poems, but Heaney makes his customary use of enjambment and an almost prose-like grammatical structure in Blackberry-Picking. Heaney quite often uses rhyme - "clot... knot", and near-rhyme, "sweet... in it", but without making it intrusive.
The words, densely packed, peppered liberally with verbs and adjectives, establish the tone. It is intentionally almost too rich. The poem fills the mouth as the blackberries do. The poem becomes hypnotic in its unrelenting linguistic intensity. However, the poet is careful to balance the copiously sonorous phrases with words that more than hint at a darker side to the bounty of blackberries.
Heaney makes scant use of any pronoun in the first part of the poem. There is a reference to "you", used in an impersonal, educational manner - "you ate the first one... ", and a reference to "we" and "our". It is, however, the blackberries that are allowed to dominate this part of the poem. The second part allows the speaker and his unnamed companions to intrude upon the opulent nature of the blackberries. However, all their emotions are involved in the "lovely canfuls".
The "lust" for blackberries is a blood lust. Their "flesh [is] sweet", like "blood". The children are willing to suffer a great deal of pain to satisfy "that hunger". Then Heaney's tone becomes decidedly ominous - the blackberries are "like a plate of eyes", their palms are stained with the juice, as "Bluebeard's" were stained with blood.
The final part of the poem is an desolate relation of the half-innocent greed of the blackberry-pickers, and their horror and jealousy at their prize's ruin. They "hoard" the blackberries in the way that the "rat-grey fungus... glut[s]" on it. It continues in the petulant tone of an upset child - "It wasn't fair/That all the lovely canfuls smelt of rot" and concludes in a more distant, grave, accepting tone, revealing that even the child knew the berries would not "keep".
The luxurious rhythm and language of the poem leads to an indulgent, but slightly oppressive mood, as if the reader is immersed in the "heavy rain and sun" of "late August". The desire for the blackberries is half-sickening, a hunger that is more in the mind than in the stomach drives the pickers. They are possessive and greedy, picking even the unripe "green ones", filling a "bath". The disgust at the "rat-grey fungus" is half horror and half envy. How dare it destroy the "sweet flesh"? The child is desperate for more, each year he yearns for more blackberries, though he knows their fate.
Heaney makes extensive use of poetic devices in Blackberry-Picking. Examples of his alliteration include "first... flesh", "peppered... pricks... palms", "berries... byre", "fur... fungus", "fruit fermented... flesh" and "sweet... sour". Heaney also uses a vocabulary rich with varying sounds, so that saying the poem is rather like eating the blackberries, it is "like thickened wine". Similar sounding words are used frequently; "milk-cans, pea-tins, jampots", "hayfields, cornfields", "trekked and picked", "fungus, glutting", meaning that the poem much be read slowly to savour its resonant cadences.
There are three primary images in Blackberry-Picking. There are the child blackberry-pickers, carrying "milk-cans, pea-tins, jam-pots", the "fur" that steals their treasure, and the blackberries themselves.
The children are an image of unrestrained desire. They succumb to the "lust for/Picking" easily, savouring the sweet taste of the first berry, but hoarding the rest in numbers they cannot possibly consume. They are controlled by their craving. They, too, represent humanity in the poem, in their envy of that which is "gutting on [their] cache", and their sense of injustice - "it [isn't] fair" that what they have so greatly desired and gained is snatched from them by the swift processes of time.
The "fungus" is the first explanation called by the speaker for the destruction of their "cache". It aids in the destruction of their fruit, and is the object of their hatred and derision. However, "once off the bush... the sweet flesh would turn sour" by its nature. The speaker knows this, although he does not acknowledge it to the end of the poem.
The blackberries attract several differing connotations. First, they are part of childhood, a yearly summer ritual, an object of enjoyment, of "trekk[ing] and pick[ing]" throughout the countryside. The childhood-pleasure aspect of blackberry picking is emphasised by the children's choice of containers - household objects, cheap and in easy reach.
Next, the blackberries are intensely desirable, they are "glossy purple", they have "sweet flesh", they "tinkl[e]" pleasantly when thrown into a container. It is their richness that is so desirable, their contents "summer's blood".
They are also ephemeral, which is part of their desirability. Every year the speaker challenges the laws of nature and "hope[s] they [will] keep". Even as the picking days are continuing the berries grow from "green" to "red" and finally "ink... up" to "big dark blobs". They change inexorably, finally, "once off the bush" and finally "smel[l] of rot".
Finally, the blackberries corrupt. Only "at first [can] just one" be eaten. The pure enjoyment of the eating is subsumed by greed for more, until finally, most are lost to the processes of time, when they should have been left on the bush. The pain involved in getting them is multiplied when they are consumed by an outside force, the "fur".
Blackberry-Picking explores the dissatisfaction often involved in gaining an object of desire. Heaney is unveiling greed. The unrestrained quest for more of the same, for greater amounts of fulfilment leads to the destruction of the object of desire. Removed from its home in the sun, and hoarded, life is slowly destroyed, changed beyond recognition and enjoyment by hostile forces and by time.
Often, however, the lesson is not learnt. A recurring delusion takes hold, where there is a perpetual consciousness that life, love and youth do not "keep", but the temptation for another try is always succumbed to.