Important Information on Roses

Cold Hardiness

• Roses can be grown in every region of the United States, but in U.S. Department of Agriculture hardiness zones above zone 5, they can be grown year-round. Gardeners who are located in zones 5 and below should choose varieties that withstand overwinterizing, such as hybrid rugosas, modern shrubs and some of the large flower climbers, according to RoseFile.

Fertilizing Roses

• Roses require an annual fertilizing schedule that varies depending on the variety of rose. A general-purpose fertilizer such as 10-10-10 or 20-20-20 used in increments of ½ to 1 cup per plant in early spring is sufficient for species roses, according to the University of Illinois Extension Service. Other varieties benefit from an additional application around June 15th. Continuous-blooming varieties require a third application in mid-July.

Pruning Roses

• According to the All-America Rose Selections site, you should prune your rose bush in winter or early spring when the plant begins to show signs of new growth. Cut the branches that are obviously dead or damaged first. Then cut away all but four or five healthy main stems. You should cut back the stems by 1/3 to ½ of their length. These cuts should be made right above outward-facing buds. This encourages the bud to grow upward and outward for the best shape.

Winterizing Roses

• Roses must be protected over the winter in areas of the United States where temperatures fall to below 20 degrees Fahrenheit, according to Danny Lipford. For best results, stop fertilizing roses in early August. Also, stop removing dead flower heads. These should be allowed to form "hips," which will tell the plant to stop growing. Remove all leaf litter from the area under the plants, as well as 1 inch of the mulch to prevent it from harboring diseases over the winter. Finally, water the plant deeply to sustain it over the cold months. Protect the plants with rose cones or cut them back to 2 or 3 feet and add 1 foot of soil and a light layer of mulch around their bases to keep the stems and roots protected.

Rose Pests and Diseases

• Different varieties of roses are resistant to rose diseases. Blackspot, powdery mildew, botrytis blight and stem cankers are fungal diseases that can destroy rose plants. These require careful maintenance and treatment with fungicides. Aphids, thrips, Japanese beetles and and spider mites are just a few of the pests that can infest rose plants. Insecticidal soap and other methods recommended by your local agricultural extension service may be necessary to manage outbreaks.