Why are the leaves of my hostas turning brown and lacy?

Answer #1 · Brent Wilson's Answer · Hi Anita,

Without seeing the plants it's hard to say exactly what is causing the brown and lacy leaves. My first guesses would be either slugs or deer. Too, towards the end of a very hot and dry summer sometimes hosta lily will start to go dormant early. The brown leaves could also be caused by sun scorch or a viral or fungal disease.

Slugs can be controlled with a Slug & Snail Bait or by placing jar lids filled with beer in the areas where you see slimy trails.

Not sure what variety of hosta you have but most varieties prefer shade, filtered light or morning sun with afternoon shade. Direct afternoon sun, particularly in the South, can and will cause leaf scorch.

Anthracnose is the most widespread foliage disease of hosta. Infection can degrade the appearance but plants are seldom killed. This disease is brought on by wet foliage from rain, dew or overhead irrigation combined with warm temperatures during the summer. Anthracnose fungi on leaves causes large irregular spots with black borders. Watering early in the day, keeping the plants cool by planting in the shade, and removing infected leaves can control or prevent spread of the disease. Fungicides are only effective for prevention so aren't practical for home gardeners.

Fusarium is a common fungal root rot organism that has been reported on hostas primarily in plant nurseries in the Southeast United States but rarely in home landscapes. Since it attacks the roots of the plant, it ultimately leads to severe wilting and death of the plant. The crown may be covered with brown pockets and the roots will be brown or black instead of whitish as healthy roots appear. In less severe cases, the plant may be stunted, have low vigor and does not emerge well in the spring. This is a soil borne fungus in which there is no cure. Diseased plants should be removed and discarded.

Southern blight of hosta also called white mold, petiole roty and crown rot is caused by the fungus Sclerotium rolfsii. The disease commonly attacks the plant at or just below the soil line. Symptoms occur after warm and rainy weather. The first symptom is a yellowing and wilting of the foliage fro the margin back to the base. The fungus produces a large amount of cottony white, thread like material called mycelium, which can grow up the stems of plants and also spread out across the soil to infect other plants. There's no surefire cure for this disease. Infected plants should be removed and discarded.

These things being mentioned, I'm not really sure what the problem is with your hosta. If it's leaf scorch pr damage from slugs or deer, your plants should recuperate and emerge okay next year. In the meantime, remove any damaged foliage this year.

If you can upload a picture this might help with a proper diagnosis. Click on the "Upload A Picture" link to the right of your name and next to the "Edit your question" link above.

Brent)