The catalogue description was wonderful, and your hybrid rose lived up to every glowing word. Fragrant, a pale shell pink, with large, floating blooms and distinctive dark-red stamens, your beautiful rose made the stunning statement you had hoped for, at least until this spring. Your swan is now a duckling; its dark red single blossoms make a very modest statement, if any at all. Your hybrid has reverted back to its stronger parent. Causes are several and often preventable.
How Hybrids are Created
Creating a new hybrid rose from two distinctive parents is a long and demanding process. What matters to a hybrid rose owner is less how a hybrid is created than where. Grafting joins the two kinds of roses together. Locating the graft (usually a slightly swollen area on the main stem, very close to the crown of the plant) is critical to preserving both hardy parent rootstock and the newer, more delicate characteristics of the grafted plant.
How Grafts Are Damaged
Three main events damage most hybrid grafts: injury, disease and winter-freeze. Damage caused by pruning or mowing may result in destroying the graft; this will result in the rose's reversion to the stronger rootstock characteristics. Disease can produce the same effect. Winter-freeze is implicated in most reversions; either heavy snow or ice can damage the graft site fatally. Results of damage usually mean shoots sent out by the rootstock and a new resemblance to the rootstock plant. In some cases, shoots sent out close to the damaged graft site will display some but not all characteristics of the second parent. The resulting new plant is referred to as a "sport."
Maintaining plant health throughout the year is the best way to prevent hybrid loss, or reversion. Remove dead leaves and branches, treat diseases promptly, and keep rose roots cleared from yard refuse. Follow local winter-care practices; this can vary from spreading a layer of mulch to building plant shelters or tipping plants for winter protection. These strategies will protect your graft sites and provide opportunities for your hybrid roses to flourish just as you had hoped.