What Is Wrong With My Zinnias?

Are the leaves covered with white powder?

Are there any brown spots and sores on flowers?

Are the leaves curled and yellow?

Are the leaves distorted, yellowed, and stippled?

Do the leaves and flowers have holes?

Are the leaves discolored and distorted?

Is the foliage yellowed and curled, shoots are spindly?

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 bellow to keep foliage dry. Any affected leaves should be cut off and removed.

Stem Blight is caused by a fungus that causes small reddish-brown spots with gray centers to form on zinnia flowers. Sometimes dark brown cankers form on their stems. Cut off affected flowers and discard them in the trash. Keep the area around the plant clear of weeds and dead plant debris. If blight proves to be a chronic problem in the area, spray healthy zinnias plant surfaces with a garden sulfur fungicide as directed on the label.

Distorted, 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.

Leaves stippled with yellow are caused by mites. These tiny, spider-like pests feed by sucking sap from the underside of the plants 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.

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.

Discolored and distorted leaves are caused by leafhoppers. These small, green or brown insects feed by sucking juices from leaves undersides. Leafhoppers may be the carriers of the Mosaic virus, so it is important to keep them in control. Insecticidal soap helps with severe infestations.

Various diseases caused by viruses occasionally attack zinnias. They are usually spread by insects. There is no cure for plant viruses. However, by controlling insect pests like leafhoppers, the transmission of these diseases is reduced. Dig up infected plants and put them in the trash. Do not compost them. Keep the garden area clear of weeds and debris that may harbor infection.

When zinnias are shaded they are forced to stretch to reach the light, causing them to develop thin stems. If you are growing seedlings indoors under lights, adjust the fluorescent lights to remain only 3 or 4 inches above the seedlings as they grow taller. To encourage thick, sturdy stems and compact plant shape, pinch the growing tips off of zinnia seedlings at least twice before the buds begin to form. This causes them to branch and grows denser.