I've been told you can't eat rhubarb after a certain time. Is this true because i've got some lovely rhubarb on my allotment. I think its some thing to do with acidity....
I have never heard this. It must be something to do with the plant itself. I have just harvested mine again and put it in the freezer. I know you have to be careful not to over crop.
Yes - I have heard this from an old lady in my road who said that it was due to the plant needing to retaining some vigour in the plant's crown to offset the winter dormancy. I think it was recommended to stop cutting it at the end of July (but that does seem rather early in the year).
I understand there is always oxalic acid in the leaves which is why they should be destroyed. As the season goes on this builds up in the petiole, the leaf stalk, which is what we eat.