To winterize miniature rose bushes, prune away dead blooms, scale back watering, stop applying fertilizer and add mulch around the base. If you live in USDA hardiness zones 1 through 4, place container roses in a garage or shed to avoid severe temperatures.
Apply your last dose of fertilizer in the late summer. Fertilizing roses after this point promotes new growth that is too fragile for winter. As the plant starts to wilt, trim away faded flowers, and leave the stems intact. When temperatures drop, the bush starts to shed leaves. This is the time to scale back watering, giving the plant just enough irrigation to keep the soil from drying out. Once all the leaves are gone, stop watering until spring. Add about 2 inches of mulch around the plant's base if you live in an area where temperatures drop below zero degrees Fahrenheit.
If you bring miniature rose bushes inside, let them spend at least part of every day in a location that's cooler than the rest of the house, such as the garage. Miniature roses require some time in the cold to encourage dormancy and promote new blooms. Prune miniature rose bushes in the second half of winter to prepare for spring growth.