Yes, that is an old rule of thumb. The idea is that you leave the stalks after August so that they can continue to grow and stay healthy. If you have prolific amounts of rhubarb, I’m sure it’s okay to cheat a little and harvest into September but be sure to harvest no more than one-third of your stalks at a time. Of course, if the stalks get too big, they taste woody and unappetizing so keep that in mind.
Yes, that is an old rule of thumb. The idea is that you leave the stalks after August so that they can continue to grow and stay healthy. If you have prolific amounts of rhubarb, I’m sure it’s okay to cheat a little and harvest into September but be sure to harvest no more than one-third of your stalks at a time. Of course, if the stalks get too big, they taste woody and unappetizing so keep that in mind.