Why Does My Coleus Look Unhealthy?

Are the leaves yellowing, wilting and, dying?

Do the leaves have pale areas on upper surfaces and "downy" patches underneath?

Do the leaves have large, ragged holes in them?

Are the leaves discolored, fine webbing may be present?

Are the leaves yellow and the plant looks weakened?

Are the leaves curled and yellow?

Are the leaves mottled with ring spots or black spots, often distorted, plant growth is stunted?

Yellow leaves that wilt and die usually indicate fungal or bacterial Root rot disease. Poorly drained, overly wet soil promotes rot so choose well-drained sites and add organic matter to improve drainage. Remove and destroy infected plants. Solarize the soil before replanting.

Pale areas on upper surfaces of the leaves and "downy" patches underneath are caused by Downy mildew. This fungus spreads quickly during cool, wet nights and warm, humid days. Leaves will wilt and die. Remove and destroy all affected plant parts and encourage good air circulation around plants by thining them. Water plants early in the morning to make sure they dry before nightfall.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

Spider mites often cause problems for coleus. Hose off plants when symptoms first appear. A strong stream knocks mites off plants and may give control. Introduce predatory mites. For severe infestations, spray plants with insecticidal soap or pyrethrin.

Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.

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.

These symptoms indicate Impatiens necrotic spot virus. There is no cure for this condition. To protect other plants, you should remove and destroy the infected plants. Aphids carry the viruses so use insecticidal soap or neem oil to eradicate them.

In areas with intense afternoon sun, coleus may experience sunscald. Sunscald can cause foliage to turn yellow and wilt or dry up, turn brown and become crumbly. It is recommended that coleus be planted in a location with afternoon shade.