Why Do My Sunflowers Look Unhealthy?

Are the leaves, stems and buds distorted?

Do the leaves have ragged holes in them?

Do the leaves of your sunflowers wilt?

Do the leaves of your sunflowers have white powdery patches on them?

Are the seedlings or young plants cut off at soil level?

Were your sunflowers defoliated?

Do the sunflower heads have silken threads on them?

Does the sunflower stems have small holes in them, plants may have wilted?

Do the leaves have raised, rusty spots on their undersides?

Distorted leaves, stems and buds are caused by aphids. These tiny insects can vary in color, green, pink, black, gray and completely white. They 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.

If the sunflower leaves have ragged holes in them, the culprits are caterpillars. Caterpillars of all kinds find large sunflower leaves a tasty food supply. A healthy plant can generally withstand an attack. Handpick pests or spray leaves with BTK.

Wilting leaves may indicate a lack of water or fungal wilt. Try watering your plants and if a good soaking does not perk it up by the next day, suspect fungal wilt. These fungi live in the soil and move upward through the plant. Leaves may be mottled with green and yellow and dark brown areas may appear on and within sunflower stems. There is no control; remove and destroy infected plants. Avoid replanting sunflowers in that area.

White, powdery patches on the leaves are caused by the fungal disease - Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the plants by thinning them. Keep foliage dry when watering. Affected leaves should be cut off and removed.

If the sunflower seedlings are cut off at the soil level, most likely cause are cutworms. These caterpillars can be 1-2 inches long, brown or gray. They feed at night by cutting off young plants and sometimes eating them whole. During the day, they are hidden below the soil surface. Control them by introducing parasitic nematodes to the ground. Using diatomaceous earth around your plants can also encourage them to leave your garden and find some other feeding ground.

Sunflower beetles typically feed on the leaf foliage and in small numbers or older plants may seldom hurt the plants. However, on younger sunflower plants, the first true leaves can be severely damaged or completely consumed. Most insecticides labeled for sunflower insects include the sunflower beetle and are very effective.

Sunflower moths are one of the most destructive pests to sunflowers, laying their eggs within the flowers. Once the eggs hatch, the larvae move into the flower heads to feed, ultimately destroying the plants. Spray plants with BTK with an early bloom to control sunflower moths.

Sunflower borers and stem maggots burrow into the stems of sunflower plants to feed. This can quickly kill the vegetation and other parts of sunflower plants, especially in large numbers. Insecticide sprays are ineffective. Harvest sunflowers as early as you can and destroy plant remains.

Raised, rusty spots on the undersides of the leaves are caused by the fungal disease - Rust. Leaves may yellow and die. To control this disease, rake up and destroy fallen leaves. Where the problem is severe, spray with copper.

Some environmental issues may have caused your sunflowers to look sickly. Sunflowers perform well in average soil and full sun, although they will tolerate light shade. Apply a general-purpose fertilizer once, about midway through the growing season.