The first step in planning any garden is choosing the right location.
Rose bushes should not be planted close to trees that will create competition for nutrients. Tree roots grow a great distance from the trunk and will grow into you rose bed to reach your rose food.
Rose bushes grow better when they have plenty of air circulation around them which will give them room to spread out a bit and help control fungal diseases.
Roses need to be close to a water source. Whether you hand water or have a watering system in place, your roses will need plenty of water that will easily drain through their root system. Roses do not like “wet feet”; good drainage is essential.
See also: choosing the right roses.