In older neighborhoods all over America the hollyhocks are in bloom. Their huge flowers begin low on their very tall stalk, then move upward as it ages. This is how you know to look low on the stalk to find the first capsules of seed maturing in the midsummer heat. These are the easiest seed to collect and just as simple to grow into stately plants next year.
Whenever you walk the dog or just take a stroll, reuse an opened bill envelope as seed container. It folds nicely into the pocket, and if you find a plant with seed you can pick a few of the capsules off and drop them in the envelope. Seed gathered from many plants from different locations will yield fabulous flower color variation compared to store bought.
Once at home separate the seed from all the other material to ensure there are no micro-seed eating bugs in there that could destroy it in storage. Then store in a clean envelope, RX bottle or mint tin in a cool, dry place. Hollyhock is a biennial that is best in its second year from seed. Sow it directly into the soil in spring after frost. One seed matures into a HUGE plant quickly, some of them eight feet tall! Hollyhocks from seed are a real old fashioned delight that yields an incredible free floral display.