There is a folk tradition that blackberries should not be picked after Michaelmas Day, as they then belong to the Devil. The idea behind this is that Michael cast him out of Heaven on this day and he landed in a tangle of brambles so afterwards the berries were tainted with his blood and not fit to eat. Whether the cut-off date is to be taken as the current 29th September or Old Michaelmas Day on 10th October is presumably dependent on how much of a risk the pickers wish to take!
Blackberries have not been plentiful this year where I live. But we went out on 29th September to pick sloes, which hung in inviting blue-black profusion on the blackthorn trees along the edge of the sunken lane where we usually find them. Sloes can be picked later than blackberries but we gathered them today for Gwyn ap Nudd because we were celebrating the restoration of his feast day (for which see THIS POST on the Brython Blog by Lorna Smithers). It has always been our custom to take the dregs of previous batches of sloe gin we make from them to return to the earth something of what we have taken. We did so again this year, but also took some very drinkable sloe gin from a good vintage to toast our labours and to pour a libation for Gwyn ap Nudd.
These sloes were picked on his feast day and the sloe gin we will make from them will be made for him, so he will be welcome at our winter festivities and in quiet moments or special occasions when it will be savoured.
These dark berries are astringent. The drink they make is powerfully pungent. As such it contains something of his nature. But there is no repugnance or reluctance – such as that associated with the Devil’s Blackberries – felt at the gathering of Gwyn’s sloes to infuse our gin. They can be gathered until Calan Gaeaf, even until Old Calan Gaeaf, after which they will no longer be at their best and the Cailleach’s withered fingers may claim them. But their spirit will be contained because we gathered them for Gwyn ap Nudd.
awenydd.cymru 
I hope you enjoy the gin made from the sloes picked at Gwyn’s feast day over the winter period. A great way of imbibing his presence 🙂