Starter Fertilizer Placement and Rate Suggestions Fall Planter Ideas + Simple Container Care and Maintenance If you want multiple flushes in your rose, don't forget to fertilize and prune. Roses are heavy feeders, so you'll want to fertilize them at least once a month throughout the growing Texas Mountain Laurel GreenAll 435 Sure Start Pre Plant Fertilizer 5 20 10 5lb Organic Farming Reliant on Synthetic Nitrogen Center for Sustaining Agriculture and Natural Resources Washington State University