Pennington Epsom Salt Plant Food Fertilizer, 7 lb. contains both magnesium and sulfur, which are crucial to plant growth. Pennington Epsom Salt can be used on a variety of plants such as: vegetables, fruits, shrubs, trees, flowers, and lawns. Epsom salt is very popular among rose growers. It also corrects yellowing leaves when caused by magnesium and/or sulfur deficiencies.