Roses grown in containers, such as pots, polyethylene bags, or tins, can be planted at any time of the year when the soil is in good condition. Make sure the the plants are sufficiently established in the containers to be removed from them intact, with the soil around the roots.
Plant them in holes sufficiently large enough to allow for the complete ball of soil to be placed, as it comes from the container, with little room to spare. This will allow for placement of a layer of fine new soil to surround the roots giving it a good start. Also place some of the new soil on top of the plant to give it a depth of 1/2 to 1 inch. Make sure you press the soil down firmly around the plant. If the soil is dry where you are planting the rose bush, be sure to give the plant a nice watering.
Container grown roses purchased in full growth in spring or summer need not be pruned until the following winter or spring, but container-grown roses planted in autumn or winter should be pruned the following March. It is not necessary to prune so severely as for lifted roses. Cut strong stems to 5 or 6 inches, and thinner stems to only 2 inches.
Miniature roses are most often bought during the year and kept in their containers until spring time. I enjoy buying one or two of them during the cold months to enjoy their blooms. When the weather warms, I have the choice of re-potting them and getting to use my potting bench, or just leaving t hem in their container indoors or out on the patio or my canopy gazebo to continue to grow. If you do a lot of potting and re-potting, or if you like to start seeds indoors, you should look into buying a potting bench.