When you plant a rosebush in the right spot -- full sun with rich soil and good drainage -- and prune it back each year, it produces abundant blooms for decades. In the case of the reblooming climbing rose "Royal Sunset" (Rosa "Royal Sunset"), pruning to encourage the maximum number of richly fragrant, pinkish-orange, 5-inch-diameter flowers requires season-long attention, beginning in late winter when the plant is dormant. Before you prune your "Royal Sunset," suitable for U.S. Department of Agriculture plant hardiness zones 6b through 9, for the first time, it should be at least 2 years old and have a trellis, fence, post or pergola nearby for support.
Spray the blades of your bypass pruners and loppers with household antiseptic cleaner, and wipe them dry with paper towels. This cuts the possibility of transferring any plant disease or fungus from a plant previously pruned with the tools.
Put on heavy garden gloves; leather gloves that extend over the wrists are commonly recommended for rose pruning. "Royal Sunset" is a heavily thorned cultivar.
Cut out any shoots coming from below the knobby bud union at the base of the plant with bypass pruners and any growth coming from the bud union that is gray and dead or green, but thinner than a pencil.
Cut out any canes at the base that are more than 5 years old and have become woody at the base. Untie them from the support. Aim for five to seven mature, productive canes at any one time. "Royal Sunset" blooms on the new lateral shoots on canes that are at least 1 year old, though these mature canes usually only flower well for two to three years.
Arrange remaining canes so they are fairly evenly spaced and are as horizontal as possible, and tie them loosely in place with lengths of string, strips of cloth or plant ties. Along a fence or a trellis, this may be a fan shape. When trained to a pillar, or if they have to go up a post before reaching the horizontal top of an arbor or pergola, wrapping the canes around the upright in crisscrossing spirals allows for more horizontal growth.
Cut the short stems that grow from each mature cane back above the second bud from the base, making each cut 1/4 inch above the bud at a 45-degree angle. These stems are called laterals and are where a climbing plant will do most of its blooming. The more horizontal your canes, the more flowers your plant develops.
Trim off faded flowers after the first flush of bloom; cut laterals back again to the second or third bud or leaflet from the base. Since "Royal Sunset" is a hybrid tea rose with large flowers, it needs the thicker stems that develop from lower cuts to support the weight of the large flowers.
Deadhead blooms as they recur throughout the season until late summer to avoid prompting growth that will be too tender to make it through the winter.