What Is Wrong With My Hypericum?

Are the stems covered with small bumps, cottony masses may be present?

Does the whole plant look stunted?

Do the leaves have powdery spots on the undersides?

Are the leaves covered with white powdery patches?

Is the lower foliage burned?

Is the foliage damaged during winter?

White, cottony masses, or brownish bumps on hypericum stems are caused by scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

If the whole plant looks stunted, and the roots have tiny galls on them the culprits are Root-knot nematodes. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Solarizing the soil also helps in preventing root-knot nematodes. Adding lots of compost to the soil will encourage fungi that attack nematodes.

A fungal disease, Rust, causes pale areas to appear on upper hypericum leaf surfaces, with brownish powdery spots directly beneath. Remove infected leaves as soon as possible. Remove and destroy diseased plants and all nearby yard debris before growth starts in the spring. Treat the disease by spraying foliage periodically with wettable sulfur starting several weeks before the disease normally appears in the spring.

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

Dog urine may discolor foliage and even kill branches of low growing plants along property borders. Spraying foliage with an anti transpirant gives some protection. Screen target plants or spray them with an aerosol pet repellant.

A severe windburn may damage hypericum foliage during the winter, but these shrubs usually regenerate in the spring. Minimize damage by surrounding plants with a protective material such as burlap or agricultural fleece. If this is an annual problem, move the plant to a more protected location.

Some environmental issues may have caused your hypericum sickly look. Hypericum can manage with part shade, however, they do flower best when they get plenty of sun. Overwatering can cause the roots to rot. Allow the soil to almost dry out between watering. They prefer soil with a pH of between 5.5 and 7.