To keep your roses blooming, keep them well watered and fertilized. An organic fertilizer, such as manure or peat moss, provides not only nutrients, but also aeration and drainage. The three important nutrients necessary for healthy plant growth are nitrogen, phosphorous, and potassium. The fertilizer most often used for roses contains an equal mix of these. You may want to feed your roses granular or liquid fertilizer, or use fertilizer spikes on a regular schedule. If you just planted your roses, allow about a month to pass before fertilizing to avoid root damage. Water your roses by soaking the ground beneath them, since watering the leaves produces dampness that can cause mildew and disease. Remove any flowers, petals, or canes that show signs of infection or decay. To prevent against insects and fungus, your roses need regular treatment, preferably with a rose spray that is designed to combat both of these problems. To produce large roses, allow the first bud to reach the top of the stem, and pinch off the others when they are beginning to swell. Use clean shears and cut at a forty-five degree angle. Cut thin or withered canes at the base and shorten the remaining canes by one-third of their length. For more information on roses, consult a nursery in your area.