What Is Wrong With My Clarkia?

Are the leaves curled and distorted?

Do the leaves and flowers have holes?

Are the leaves distorted, yellowed, and stippled?

Are the older leaves turning yellow and wilting, an overall decline in plant vigor is apparent?

Are the leaves covered with white powder?

Do the leaves have spots or blotches?

Distorted and curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Holes in leaves and flowers are caused by Japanese beetles, pests that can seriously damage foliage. Adults of these insects devour leaves, stalks, and flowers of nearly 300 plant species. Their larvae feed on the roots of the plants. Handpick adult beetles into a can of soapy water but make sure to wear gloves as Japanese beetles are blister beetles. Apply parasitic nematodes to the soil to limit beetle grub populations. Use pyrethrin powder or neem oil as a last resort.

Leaves stippled with yellow are caused by mites. These tiny, spider-like pests feed by sucking sap from the underside of the plant's leaves causing yellow flecking on the upper leaf surfaces. You can control spider mites by spraying plants thoroughly with water 2-3 times a day for several days. For severe infestations, spray plants with insecticidal soap.

These symptoms indicate fungal disease Verticillium wilt. Verticillium infects a wide range of plant species. Destroy all infected plants, as there is no cure. Prevent problems by presoaking seed in a 10 percent bleach solution.

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from below to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

Your plants are suffering from fungal leaf spot. These can come from a number of fungus diseases, causing spots to occur on foliage. Spots may enlarge rapidly, especially in wet weather. Destroy infected leaves or plants. Spray plants with sulfur to prevent the disease from spreading, especially if the weather is wet. Spray between rains. Prevent problems by thinning plants to provide good air circulation.

Stem rot causes blackened stems at the base and the toppling over of the plant. These problems are common when plants are kept in a place where too much shade prevents the leaves and soil from drying out. Remove and destroy infected plants and surrounding soil. Let the soil dry somewhat between waterings, and incorporate organic matter to improve soil drainage. Avoid overwatering and overcrowding. Keep winter mulch away from the crowns to prevent excess moisture.