The poem
Late August, given heavy rain and sun For a full week, the blackberries would ripen. At first, just one, a glossy purple clot Among others, red, green, hard as a knot. You ate that first one and its flesh was sweet Like thickened wine: summer's blood was in it Leaving stains upon the tongue and lust for Picking. Then red ones inked up and that hunger Sent us out with milk cans, pea tins, jam-pots Where briars scratched and wet grass bleached our boots. Round hayfields, cornfields and potato-drills We trekked and picked until the cans were full Until the tinkling bottom had been covered With green ones, and on top big dark blobs burned Like a plate of eyes. Our hands were peppered With thorn pricks, our palms sticky as Bluebeard's. We hoarded the fresh berries in the byre. But when the bath was filled we found a fur, A rat-grey fungus, glutting on our cache. The juice was stinking too. Once off the bush The fruit fermented, the sweet flesh would turn sour. I always felt like crying. It wasn't fair That all the lovely canfuls smelt of rot. Each year I hoped they'd keep, knew they would not.

I think this is alovely poem with great rythem
i like the poem alot..to me it talks about a childhood experience as well as something sexual..some happy moments as well as some sad ones.
All i can say is the poem is talking not only about the childhood experience it also shows us things like life cycle. And the thing that i think he wants to show the most is the feeling of a very happy moment(the taste of ripest delicious blackberry) and how the happy moment never last for ever, and that you can't keep the moment.(the blackberry had gone bad and tastes sour)
This poem is purely sexual. It's describing a person's first sexual experience and first love. There are two representations of change in the poem, and change in season describes the change in life. A womans first sexual experience is not usually enjoyable (painful) but after the first time, it's something that is craved.