It was a super early spring this year. My rhubarb plants, which usually start to produce seeds June – August, already have big clusters of seeds on their stalks. The stalks with seeds on them are completely hollow inside, too. Rhubarb seeds take 3 years to be ready to harvest. It is actually a vegetable, & the part we eat is called the petiole. They need a lot of sun to grow, & quite a lot of space. But once they start growing, they are extremely hardy & keep growing for a long time.