Pick the right spot
Most roses require full sun so be sure to plant in an area that receives 6 to 8 hours of sunshine a day. Too much shade will often prevent the plant from flowering and, even worse, promote fungal growth. Roses do best when they're not crowded in among other shrubs or trees that will be competing for nutrients and water. It's also important to choose a location that provides good water drainage; so planting on a sunny gentle slope would be ideal.
Preparing the hole
When planting your roses, dig a hole that is approximately twice as deep as the container and three times the width. Then fill the hole with water and let it drain. Amend the soil you've dug out of the hole with a mixture of organic matter such as compost, cow manure, and peat moss. If you're a beginner gardener, you may want to try planting shrub roses, as they are far less fussy as to the type of soil they'll grow in.
Get ready to plant
Before you put your rose plant into the ground, look it over closely. Check the plant for any dead or damaged wood and remove it as needed (clip back to about 1 inch of the base of the plant). Once you take the plant out of its container check the root system. If the roots are bound tightly around each other, loosen them gently with your fingers. Finally, put your rose in the ground, filling in the hole with your amended soil. Once the rose is planted, it's a good idea to lay down at least 2 inches of mulch around the base of the plant. This will help in protecting it from harsh winds, conserving water and keep weeds under control.
Food and drink
During the first month, newly planted roses need frequent watering. A good rule of thumb is to give the plant about an inch of water a week, but if it's particularly hot or the plant seems dry, don't hesitate to give it more water. Never pour water on top of the plant directly. Instead, water the base of the plant, ideally in the morning before temperatures get too hot. A good investment is a soaker hose that can be weaved throughout the plants making watering less of a chore. Hold off on fertilizing your new plants until they have grown accustomed to their new home (about a month). Then feed them monthly with a fertilizer rich in nitrogen or you may use any other general purpose rose food.
Watch them closely
Roses are prone to mildew and fungus so you need to check the plant periodically for any evidence of these creepy crawlies. Fortunately, there are several good commercial fungicides that will stop fungus in its tracks. Just follow the manufacturer's instructions should this become necessary.
A word about pruning
Careful pruning is necessary to encourage new growth and to shape your plant. How and when to prune your roses depends primarily on the type of plant you have. As a general rule, though, most roses get pruned in the spring. With a sharp clean pair of pruners or loppers, cut off any dead leaves or branches. Look for any branches that are "crossing over each other" and could potentially inhibit growth. Also remove any thin spindly branches from your plant. The idea is to maximize air circulation and exposure to sun. Make clean cuts, at a 45-degree angle, and make your cut approximately 1/4 inch above a bud that is facing outward. After pruning, is a good time to fertilize and inspect your plant for any signs of bugs or disease.