There are 48 different classifications of roses, according to the Colorado State University Extension and the American Rose Society. Although the rose plant is widely cultivated, and the varieties diverse, most roses grow well under specific conditions. Choosing the correct site for your rose garden, and preparing the soil in the correct manner, is vital for the long-term health of the rose garden and ensures your rose plants will continue to grow year after year.
Locate an area in your garden that gets full sunlight and good air circulation, says the University of Illinois Extension. Roses require at least 6 hours of sunlight a day, so a southerly facing portion of the garden is best.
Test the soil of your garden using a home pH testing kit or by sending samples of your site's soil to a local university extension service. Home pH kits, or the instructions from local university testing labs, will help you determine the amount of fertilizer required in your garden. Roses require a pH level between 6.0 and 7.0, reports the University of Illinois.
Add organic matter to the soil to improve drainage and fertility. Add 3 to 6 inches of organic compost, leaves or grass clippings to the top of sandy and clay soil; till the material to mix, advises the University of Minnesota Extension.
Add 1/2 lb. of superphosphate to your garden for every bushel of organic matter added, suggests the University of Illinois Extension.