This is a hybrid of Floribunda in full bloom with the inflorescences of a hybrid Tea rose, which, although slightly shorter on the stem, is still long. Shades range from light pastels to deep purples and often have a hint of sweet floral notes.
Source: Kansas City Rose Society
Gardeners love the size and shape of hybrid tea roses but the inflorescences produced by floribunda roses will find the perfect balance of both in grandiflora roses. The result of a cross between hybrid teas and flowering plants, grandifloras produces clusters of 5 to 7 large flowers on 3- to 5-foot-long canes. Some varieties can grow up to 10 feet tall, while retaining a round, bushy habit. How to care for this rose is similar to other types of roses.
Culture
Grandiflora roses grow in U.S. Department of Agriculture plant hardiness zones 5 through 9. Like other rose varieties, grandiflora grows best in full sunlight, with at least 6 hours of direct sunlight. , sunlight every day. They prefer fast-draining, fertile, loamy soil with a pH near 7.0. Planting grandifloras 6 feet apart is necessary to provide adequate air circulation and room for future growth.
Water and Fertilizer
Roses need additional watering when the surrounding soil is 1 to 2 inches dry. Watering directly into the soil, watering only in the morning will reduce the risk of fungal disease forming on the leaves. Fertilizing grandifloras with a slow-release 5-10-5 nitrogen, phosphorus, and potassium fertilizer three times per year will provide adequate nutrients. Give each application six weeks apart, starting with the first application in spring when the new plant is 6 inches long. Spread 1 tablespoon of fertilizer around the base of each plant. Mix fertilizer into the top 3 inches of soil and water the area thoroughly.
Cut
Annual pruning is important for the overall health and appearance of the inflorescence. Always prune roses in late winter while they are still dormant, just before their buds begin to bloom. Removing damaged, broken, diseased or dead plants first will increase the health of the tree. Pruning away weak shoots, stems, and branches that cross or rub against other plants will resolve the problem areas. Pruning the remaining plants, removing the oldest plants first and leaving three to seven of the healthiest, will rejuvenate the tree. Trim the top third to half of the remaining sticks to control height. Ensure proper growth in the future by cutting each branch a quarter of an inch above the outward facing or side branch.
Maintenance
Spreading a 1-inch-deep layer of mulch around your granidflora inflorescence will control weed growth while reducing moisture loss and insulating the roots. Periodically inspecting leaves for signs of disease and insect infestation is important for maintaining plant health. Spraying roses with a fungicide in the spring during prolonged wet weather will help protect against fungal diseases. Using insecticidal soaps and horticultural oils on plants infested with aphids, scale, and whiteflies will get rid of these pests.
