Did you know that one of the most perennially popular garden plants is also our national flower? The rose was designated the official flower and floral emblem of the United States of America in 1986. The popularity of roses has rapidly gained ground in recent years thanks to breeding improvements and plant selections over the last several years; ‘Candy Oh! Vivid Red’ is a product of the breeding efforts of David Zlesak of St. Paul, Minn.
‘Candy Oh! Vivid Red’ is a must-have garden rose that sweetens the landscape with loads of perpetual blooms. Large sprays of single, candy apple–red flowers blanket the dense, mounded foliage from early summer to frost. It thrives in full-sun locations throughout USDA Hardiness Zones 4 to 9 and reaches 3 to 4 feet tall by 3 feet wide at maturity.
It makes an excellent landscape rose but also is often used as an accent plant, cut flower or part of mixed and mass plantings. ‘Candy Oh! Vivid Red’ is a low-maintenance plant that does not require deadheading to encourage continuous bloom or additional overwintering protection. Additionally, it is resistant to numerous plant pathogens including black spot, mildews, and rust diseases.
With its profuse blooms, ease of production, and superb landscape performance, ‘Candy Oh! Vivid Red’ is a must have and will hold its own when compared to other rose varieties on the market.
Rosa ‘Candy Oh! Vivid Red’ (‘ZieMartinCipar’ PPAF) is vegetatively propagated by a limited number of licensed propagators, and self-propagation is strictly prohibited. Rooted liners are available in various sizes; see page 52 for a listing of the current licensed propagators.
‘Candy Oh! Vivid Red’ is best suited to 1-gallon or larger containers. For large container sizes (8-inch and up), plant them in the late summer, bulk them up and overwinter them in their final containers. Smaller container sizes also can be planted in the summer or spring using dormant, vernalized or fresh liners.
Roses perform best when they are grown in a moist, well-drained medium with good water-holding capacity. The liners should be planted so the original soil line of the plug is even with or just below the surface of the growing medium of the new container. Pinching is not always necessary, particularly when plants are grown in small containers; however, many growers have found it beneficial to pinch or trim them just before or shortly after planting to encourage good branching. With large containers, it is not uncommon for growers to trim them back once or twice during production to achieve a fuller-appearing plant.
Roses are moderate feeders. During production, maintain media pH between 5.6 and 6.4. Growers using water-soluble fertilizers either feed with a constant liquid fertilization program using rates of 100- to 150-ppm nitrogen with each irrigation or apply 250-300 ppm of nitrogen as needed. Growers often incorporate controlled-release fertilizers into the growing medium before planting, at a rate equivalent to 1.0 to 1.25 pounds of nitrogen per yard of growing mix.
Roses should be kept evenly moist throughout production. When the growing mix dries down too much, lower foliage can turn yellow and abscise from the plant. When irrigation is necessary, water the plants thoroughly and allow the growing medium to dry only slightly between waterings.
When producing Rosa ‘Candy Oh! Vivid Red’ in containers, height control is often necessary. Providing adequate space between the plants helps reduce plant height during production. The plants can be trimmed to maintain an appropriate height and appearance; keep in mind that it will take four to five weeks for the plants to produce another flush of blooms after they have been trimmed back. If growth regulators are needed, consider multiple spray applications of 60- to 90-ppm paclobutrazol (Bonzi, Paczol or Piccolo). Begin PGR applications about one week after trimming and reapply them at seven- to 10-day intervals if additional control is necessary.
Insects and Diseases
Aphids, Japanese beetles, spider mites and thrips are commonly observed feeding on roses. Depending on the production environment and situation, all of them have the potential to cause significant damage to rose crops. It is very important for growers to scout regularly to detect these pests and to determine when control strategies must be implemented. Many growers implement proactive strategies during production to reduce or eliminate the populations of these insects and mites.
Although ‘Candy Oh! Vivid Red’ is resistant to numerous diseases that commonly infect roses, the occurrence of these diseases is still possible. Be on the lookout for black spot (Asteroma, Coniothyrium and Meliola), Botrytis, downy mildew, leaf spot (Mycosphaerella), powdery mildew and rust diseases. This plant’s disease resistance, coupled with good watering practices, adequate plant spacing and plenty of air circulation, can prevent the occurrence of most diseases under most circumstances. These diseases can be detected with routine crop monitoring.
Compared to many perennials, ‘Candy Oh! Vivid Red’ makes it relatively easy to produce flowering plants. It does not require cold for flowering; however, many growers will receive vernalized and/or dormant liners for planting because most propagation occurs during the summer months.
Vernalized liners have been bulked up and are ready for transplanting into large containers.
Because it doesn’t require vernalization for flowering and is a day-neutral plant, producing flowering roses is mostly a function of temperature and time. The best quality plants are produced with day temperatures of 68-75° F and 60-65° F at night. At these temperatures, it generally takes 10 to 12 weeks to grow a 1-gallon container. The timing of the crop will vary somewhat depending on the size and stage of the starting materials (dormant versus actively growing) and whether the crop was trimmed or pinched. Remember, when the plants are cut back to promote branching, it takes an additional four to five weeks (from the time they are trimmed) for them to develop flowers.
Rosa ‘Candy Oh! Vivid Red’ is marketed under the Proven Winners brand; rooted liners can be obtained only from licensed Proven Winner propagators including Spring Meadow Nursery Inc. (www.spring  meadownursery.com) in Grand Haven, Mich. Finished containers are widely available from many reputable greenhouses and nurseries across the country.