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What Do Roses Need When They Bloom With No Leaves at All?

Growing healthy, beautiful roses requires a proactive maintenance program. Because roses are susceptible to a host of insect and disease problems, an ongoing schedule of care is advised by The American Rose Society. Preventing problems before they present themselves means the difference between lush, green foliage with healthy flowers and sparse blooms held atop leafless stems.
  1. Proactive Maintenance

    • For healthy growth, roses need a basic pest control program including proper site selection, good soil preparation, good drainage, proper spacing, cultivar selection and plant maintenance. A preventive spray regimen considers that roses become resistant to specific chemicals over time. Gardeners should rotate products with different chemical agents that have the same desired effects so roses do not built up fungicidal resistances. Although roses can survive without a spray regimen, they may not thrive in the absence of one.

    Black Spot

    • Black spot is a common and serious rose disease that often reaches epidemic proportions in a single season, according to the Clemson Cooperative Extension. This fungal disease progresses over the growing season, resulting in complete defoliation of plants in severe infestations. Leaves infected with black spot produce ethylene, which is a plant hormone that promotes leaf drop. Rose bushes can be denuded of foliage and still retain blooms at the ends of their stems. The American Rose Society recommends spraying with a fungicide at seven- to 10-day intervals to prevent black spot fungus.

    Downy Mildew

    • Downy mildew is a highly destructive disease that causes severe and rapid defoliation. Differing from powdery mildew, which coats leaves with a white powdery film, downy mildew manifests itself as dark lesions on leaves. Roses need regular fungicidal applications to prevent infection from this disease and receive protection against defoliation. Purdue University Extension cautions that beginning a spray regimen after downy mildew symptoms appear will not control this disease.

    Aphids and Mites

    • Severe aphid and spider mite infestations also can cause leaf drop. Both insect pests suck juices from leaves, which removes the chlorophyll. Leaves appear yellowed or spotted before they drop. Roses need frequent monitoring for the presence of aphids and frequent water jetting from a garden hose to remove them. Spider mites can be controlled with water jetting, miticides and insecticidal soaps that are packaged specifically for use on roses.