An essential step in preserving hollyhock seeds is to collect only seed capsules that are brown, papery-dry and beginning to split open. This minimizes the occurrence of mold and mildew during winter seed preservation. The best storage area for preserved seeds is one that is cool, dry and dark.
To keep colors and varieties straight, collect seed capsules by using labeled paper bags and placing the seed capsules into the appropriate sacks. In a sheltered spot, sort the seeds by spreading out the contents of each bag on a cookie sheet or other clean, flat surface. Separate the seeds from the pods and chaff, discarding seeds with insect holes, and retaining only firm, undamaged seeds. Store the seeds in a paper envelope, label it with the variety and year, and place the envelopes into a canning jar or other air-tight container. Plant preserved hollyhock seeds the following year.