No, it is fine for rhubarb plants to grow flowering stalk, but you must remember to remove those flowering stems so that the plant will put all its energy into leaf production. Delay harvesting any of the rhubarb leaves the first year, sample just a few leaves the second year and after that never remove all the leaves from the plant or it will weaken the crown. Harvest the stems by pulling them off not by cutting as leaving bit of stalk on the crown can attract insects and disease. Rhubarb must have a winter cold spell to thrive and loves cool, moist weather. Shade the soil around the base of the rhubarb with composted manure to keep the soil cool. Rhubarb does great in containers and the huge leaves have a tropical look - but be sure to use a large pot at least 24 inches deep so the roots will stay cool in the summer. Avoid clay or metal containers that can hold heat. A half whiskey barrel makes a fine home for rhubarb especially if you can place it where it is shaded from the hot afternoon sun. I grow my rhubarb under a clematis covered arbor. This way the plants get lots of sunlight in the spring and then in the summer the foliage of the clematis creates a shaded bower, and the rhubarb can rest all summer without any danger of sunburn on the giant leaves. Keep growing, Marianne Binetti