Problems With Growing Zinnias

Care

• Choose a sunny, well-drained location for zinnias. These easy-to-grow annuals prefer full sun for colorful flowers. Zinnias require good air circulation. Vulnerable to fungus and mildew, zinnias are watered at their roots, not by overhead sprinkling, and they need breezes or space between plants so that foliage dries quickly when it does get wet. Balanced fertilizers labeled for annual flowers provide the nutrition for healthy plants. When zinnias are deadheaded regularly, they typically bloom from May to September. Popular as cut flowers, zinnias thrive in gardens and borders. They are drought tolerant for short periods. Heat-wilted zinnias perk up when root-watered.

Pests

• Zinnias are plagued by a few insects, notably aphids and spider mites. Look for them on the underside of leaves or on flower stems. Use insecticidal soap or any commercial insecticide suitable for flowering plants. Because these insects carry fungus disease from one infected plant to other plants, they should be discouraged. Slugs are fond of zinnia leaves. Check for slime trails around the base of the plant or on damaged leaves. Use your favorite slug and snail control around the zinnia bed. Caterpillars may attack zinnias, but are easy to spot. Pluck them off by hand or use insect powders or sprays that target chewing insects.

Disease

• Because zinnias are prone to fungal diseases such as powdery mildew and leaf blight, space these plants to avoid overcrowding. Check the plant label and follow directions for plant spacing. Thin plants as needed to maintain air space. Massed together with foliage touching, these flowering plants quickly succumb to damp, mildew-spreading conditions. Remove diseased zinnias promptly and replace them with hardy cultivars. Look for hybrids bred to resist diseases. Zinnias suffer root rot when their roots get too much water. Well-drained soil and a sunny location cut down on root problems.

Benefits

• Zinnias suit most gardens. Select cultivars for your hardiness zone and space. These annuals grow quickly, typically blooming six to 12 weeks after seeds are sown. With the proper plant selection and minimal care, zinnias provide a profusion of color. Given room to grow, zinnias mature as bushy, flower-laden plants that last all season. They partner well with wildflowers and marigolds for a low-care sun garden.