Why Does My Hollyhock Look Unhealthy?

Are the leaves and petals pale, silvery?

Do the hollyhock stems break off easily?

Are the leaves discolored, foliage may be webbed?

Do the leaves and flowers have holes?

Are the flowers deformed or dwarfed, appearing mostly in late summer?

Do the leaves have large, ragged holes in them?

Do the leaves have reddish or pale yellow areas on their upper side and dusty orange blisters on the undersides?

Do the leaves have moist or brown spots on them?

Pale, silvery hollyhock leaves, and petals are caused by thrips. Thrips are tiny, yellow to black flying insects. They hide under leaves and inside flowers. Severely infested plant parts should be pruned off and destroyed. Control thrips by introducing lady beetles or lacewings. Insecticidal soap helps in severe infestations.

Stalk borers are long, thin, striped caterpillars that eat their way through stalk centers. Small, round stem holes may betray their presence.

Spider mites are known to cause problems for hollyhock. 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 or pyrethrin.

Holes in leaves and flowers in hollyhock are caused by Japanese beetles. 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.

Tarnished plant bugs inject a plant-deforming toxin as they feed on flowers and leaves. Trap them with white sticky traps or treat plants with a commercial pyrethrin spray or dust in the evening to control severe infestations. The best way to prevent this pest is through a thorough fall and spring cleanup. This will prevent it from overwintering.

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.

Likely cause for these symptoms is a fungal disease - Rust. Provide good air circulation around plants by thining them. Avoid making leaves wet when watering. Remove and destroy all garden debris before spring. All infected leaves should be removed. Spray leaves with sulfur early in the season to prevent rust or to treat mild infections.

Your hollyhock might be suffering from Anthracnose or some other fungal leaf spot. 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. Prevent problems by thinning plants to provide good air circulation.

If the stems are with lesions, and the foliage is wilted the cause may be the stem canker. A fungal stem canker attacks hollyhocks at bloom time on rare occasions. Stem lesions are first dark brown and later ash-gray. As these spots girdle the stem the part above wilts, collapses, breaks off, and dies. Remove and destroy infected plants or plant parts as soon as you notice them.