Posted: 13/02/2015 at 07:41
I've been told that you shouldn't pick Rhubarb later in the season (nor blackberries either) as the poison from the leaves starts to be drawn back down the stalks. Can anyone confirm this please?
You shouldn't pick rhubarb later in the season because the nutrition/energy in the leaves needs to be reabsorbed by the roots/crown otherwise you will have a weak and unproductive plant the following year. Nothing to do with the toxic oxalic acid in the green part of the leaves.
As for blackberries, any on the plant late in the season are likely to be less sweet than the earlier ones due to lack of sunlight, that's the only reason for not picking the later ones. There's an Old Wives' tale that says on 30 September the Devil trails his coat-tails over the hedgerows making the blackberries taste bitter.