Is it a myth or fact to not pick rhubarb after the Fourth of July?

It's a fact that many gardeners advise against picking rhubarb after the Fourth of July. This guideline is based on the plant's growth cycle; after this date, the leaves can become toxic and the plant may start to store energy for winter, leading to less flavorful stalks. Additionally, allowing the plant to mature helps ensure a healthy crop for the following year.