Answer: Unfortunately, without a description of the damage it is a bit difficult to make suggestions. If the plants are being chewed off whole or in large pieces, the possible suspects would include groundhogs or woodchucks. These animals are unpredictable and potentially quite dangerous and are best removed by an animal control specialist. Rabbits may also dine on these plants and can be excluded from the garden by a wire mesh fence.
During the spring there are several insects that might feed on these plants. If there are small squiggly lines on the foliage, it is possible you are seeing damage caused by leafminers tunneling through the leaves. This can be controlled to some extent by removing the leaves to prevent the insect from spreading.
Plant bugs (eg tarnished plant bug) can leave actual holes in the foliage and can be controlled in the nymph stage with insecticidal soap.
Several types of caterpillar will feed on hollyhocks and can be controlled (if necessary) with Bt (Bacillus thuringiensis).
I hope this helps you trouble shoot. If none of these sound like the cause of the damage, you might want to take a sample to your county extension for help in a more specific indentification of the problem and suggestions as to what steps to take.
Q&A Library Searching Tips