Flower stalk formation may be caused by drought, infertile soils, and extreme heat. Age may be another factor. Old plants tend to flower more than young ones. Flower formation can be discouraged with good cultural practices. Water rhubarb plants once a week during dry weather.
Manure is an alternative to a commercial fertilizer.
Apply a 2 to 3 inch layer of well-rotted manure around rhubarb plants in spring. Dig and divide large, old rhubarb plants in early spring or late summer. While the rhubarb leaves do contain poisonous materials, they can be used in the compost pile. Oxalic acid and soluble oxalates are not readily absorbed by the roots of plants. Compost containing decomposed rhubarb leaves can be safely worked into the soil of vegetable gardens.