Roses add an elegant and classic tone to your flower garden, with hundreds of varieties to choose from and a wide choice of colors. Roses need a little more attention to care, however, especially if you live in areas where cold temperatures can threaten tender plants or where hot temperatures call for additional watering of these water-hungry plants. Learning the ideal temperatures for roses can help you extend the life and beauty of your roses.
Choosing Rose Plants
Gardeners should consider their climate conditions in choosing the roses that will grow most easily in their areas. Some varieties, like shrub roses, are hardier in cold climates. Growing roses in hot climates can be challenging with afternoon sun and ongoing periods of high temperatures. Shrub roses or climbing roses can survive these conditions, as well as some varieties of old roses.
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Ideal Temperatures for Planting Roses
Plant roses in early spring after the ground has thawed and after all danger of killing frost has passed. Frost dates can vary greatly from one area of the country to another. Consult your local agricultural extension service or garden club for information on the proper date. Roses cannot withstand temperatures below 32 degrees F, so keep plants awaiting transplanting in a warm, protected area where they will not be damaged.
Ideal Temperatures for Propagation
Take cuttings from your rose plants from early June to mid-August when new growth hardens. Cut a stem that has bloomed down to the first five-leaflet leaf, remove the bottom leaf and top leaf. Wet the bottom half inch of the cutting and dip into powdered rooting hormone. Cover with plastic and put into a cold frame or other location out of the sun. Cover with compost when temperatures fall. Ideal temperatures to keep cuttings over winter are from 25 to 35 degrees F.
Protection From Cold Temperatures
When frost threatens, it's time to take measures to protect rose plants from the cold. Protection methods seek to keep the plant uniformly cold and frozen throughout the winter, eliminating the freezing and thawing that can damage plant cell structures. You should not cover the plant too early in the season, according to the University of Illinois Extension Service. Wait until a killing frost causes leaves to drop.
Remove any remaining leaves that may harbor disease, then mound soil at the base of the plant or cover with a Styrofoam rose cone. Larger rose shrubs can be bent to the ground and covered with soil, taking care not to break stems.
Protection in Hot Temperatures
To protect delicate rose plants in hot temperatures, use a shade cloth to shield them from the hot afternoon sun. Provide some shade when afternoon temperatures rise above 80 degrees F. Plan on additional watering during dry periods, and spread a light mulch over the plants to retain water and keep roots cool. Remember to pull the mulch back several inches from the plant's trunk. Because hot temperatures tend to reduce blooming, pay special attention to deadheading your rose plants.