Hollyhocks

Hungry caterpillars, sawflies and Japanese beetles can cause the damage you describe.  The worm-like caterpillars and sawflies usually hide under the leaves or along the stems during the day and feed at night out of sight.  Japanese beetles, on the other hand, are easy to spot.  These numerous small coppery-green beetles eat and mate in broad daylight. I choose to cover up the damage on my hollyhocks rather than control the insects.  Medium sized plants like ornamental grasses, daylilies and other perennials mask the unsightly foliage. This is less work for you and kinder to the environment.  The plants can usually tolerate the damage, it just looks bad.  If you can’t tolerate the problem or the Japanese beetles are decimating the plants, you can use an insecticide.  Select one labeled for controlling these insects on flowers.  Look for one of the more environmentally friendly products like, Neem, that kills many insects and deters Japanese beetle feeding or insecticidal soap that kills insects on contact with no residual control.  And as always read and follow all label directions carefully.