Roses are popular, whether for scent, color or structure. Almost everyone can grow roses like vines, shrubs, hedges, groundcovers, or even in containers. There are a few standard practices to keep roses thriving in our hot, windy summer weather.
JoAnne Skelly
Some roses may need afternoon shade so that the plants don’t go semi-dormant and cause flower production to dwindle. They need to be kept away from hot reflective surfaces.
Removing spent blooms, or deadheading usually promotes additional blooms. Some roses, such as my old red ramblers, only bloom once and no amount of deadheading will increase the bloom time. Think of cutting off old blooms as a form of gentle pruning. Use sharp shears and disinfect between cuts. Cut the flowers back to just above a set of five leaflets rather than a set of three. Don’t leave a stub. I always seal cuts with white school glue or wood glue to prevent borers from getting into the stems.
Watering frequency depends on weather conditions and soil type. Sandy soil drains quickly and requires more frequent watering. Clay soil holds water and can go longer between irrigations. Windy and/or hot days will make the plant lose water more quickly. New plants with less well-developed root systems will need more frequent watering until they are established. Big established plants with lots of leaves can use a lot of water. Water to a depth of 12 inches to 16 inches.
For the best performance, roses thrive being fertilized every two to four weeks through the growing season. Alternating between organic fertilizers, which not only feed the plants, but also support soil microbial health, and traditional inorganic fertilizers can work well. The American Rose Society suggests a 6-12-6 (nitrogen-phosphorus-potassium) analysis as a balanced rose food. When I looked at product labels I found many differing analyses: 6-9-6, 12-6-10, 4-3-2, 4-6-2, 12-4-8, 10-8-4, but not 6-12-6. Try to find a product with the phosphorus level higher than the nitrogen or potassium.
The primary rose pests are aphids, cane borers, powdery mildew, weeds and deer. With our dry weather we rarely have other mildew or black spot diseases. Although in humid parts of the country, overhead watering is discouraged because it increases disease problems, in Nevada, hosing off roses daily to every couple of days is advised to reduce powdery mildew, which thrives in a dusty dry environment. Hosing off also works against aphids if done daily during infestations.
More on fertilizing roses next week.
— JoAnne Skelly is an Associate Professor and Extension Educator, Emerita, University of Nevada Cooperative Extension. She can be reached at skellyj@unr.edu.
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