Hosta and hollyhock damage

Asked June 25, 2019, 9:28 AM EDT

I'm suddenly noticing lots of damage to the leaves of my hostas and hollyhocks. Is this due to the extremely wet spring, or do I have a bug problem that we need to treat?

Monroe County Michigan

1 Response

Hello,

The hostas are being eaten by an insect, most common are slugs in the evening. Or possibly earwigs or some caterpillars. Turn leaves over to see if there are insects. And check at night with a flashlight to see if slugs are present. Severely damaged leaves can be clipped off from now through mid-July, and the hosta will eventually push out new leaves. Insecticides for slugs; or gravel or diatomaceous earth can be applied to the ground around the hostas under the leaves. Slug traps do work, but you need to empty them.

The hollyhocks have a fungal disease. Our wet spring has made this an early issue this year. Use mulch around the base of the plants, clip off the severely damaged leaves, and spray with a fungicide whose label lists hollyhock. Repeat sprays according to the label during wet weather. The fungicide will slow progression of the fungus, but won’t “ cure” any damaged leaves. Water them without getting the leaves wet, and redirect lawn sprinklers so they don’t get wet.

Here are some references for you-

http://hyg.ipm.illinois.edu/article.php?id=378

https://hort.extension.wisc.edu/articles/slugs/

Thank you.