Depending on the time of year you purchase your roses, you will have a choice of types of roses:
Bare-root roses: These are only available from about November to March usually mail order. These are plants dug from open ground and packed to prevent the roots drying out before sale. Bare-root plants are usually good quality, having a wider root spread than containerised plants, and they are often good value. They should be planted as soon as received, or if ground conditions are unsuitable, unpacked and kept in a container of slightly moist compost and planted as soon as conditions allow.
Containerised roses: These are at their best in garden centres from about November to March. They may be available to buy like this for longer into the spring and summer, but quality starts to suffer the longer they are kept on display. They are bare-root roses placed in pots of potting media to prevent them drying out. They should be planted as soon as received.
Container-grown roses: These are available all year round. These are roses that have been grown in containers for a whole growing season or more. They can be planted at any time, (but are usually not such good plants as bare root ones) and are comparatively costly.