Here’s a fun tip: you can eat hollyhock flowers and still have all the seeds! Just wait until the flower is about to fall out, and tug it out gently. It’ll slide right out of that seed pod that’s currently ripening seeds. If you wait another day or two longer, it’ll fall to the ground, and you can pick it up off the ground. (I mulch everything in wood chips, so when the flowers fall to the ground in my garden, they don’t get dirty.) I’ve found that if I check my hollyhocks every other day or so and gently tug out any flowers that have dried up, very few fall to the ground, and they’re the ideal flavor at that stage.
I’ve never picked unripe seed pods on purpose, because I always want the seeds! But I’ve eaten some that have gotten knocked off the plant because I was a klutz while walking past them. They’re very good, and so are the tiny leaf buds that appear before they start flowering. I just, well, want the flowers and seeds more than I want the green seed pods or leaves, so I don’t harvest those on purpose! 
I also don’t tend to harvest the roots on purpose because I’d rather leave those tasty drought tolerant perennial ornamental plants alone to give me more yummy flowers next year. But sometimes I’m digging around them to harvest sunchokes or something, and I find a big fat hollyhock root in the way, and I’ll snap it off and take it inside to eat. They’re a bit rubbery in texture, and very mucilaginous, but not at all woody, despite my plants being perennial and getting very little water. And they taste just like carrots, and they cook down into softness faster than carrots (although not as fast as skirrets), so they’re perfect to chop into pieces and add to a stew.
By the way, I’m inclined to harvest most of my edible flowers that way: I wait until the petals are dried up, right before they’re about to fall off the plant, and then I collect them. This seems to work great for roses, tulips, hollyhocks, and sego lilies. (I finally got some sego lilies to grow in my garden this year! 
) They all have the maximum flavor that way, they’re already dried, and I don’t lose any of the time of the flowers being pretty. I also don’t have to give up any seeds. The timing can be a bit thin — there’s usually a one or two day window in between the petals drying up and falling off, and if the wind decides to blow hard during one of those days, I’m outta luck for those flowers.
I haven’t tried harvesting violet flowers dried yet, because they’re so tasty raw, and so tiny, and there are never nearly enough, so I tend to just eat them all straight from hand to mouth whenever they first appear. 
Oh, I also haven’t bothered eating everlasting pea flowers dried. I just pop them straight into my mouth. There are new everlasting pea flowers every single day all summer, so they’re a snack while I’m out in the garden.
Oh, and bellflowers and common mallow flowers . . . those I just pop into my mouth as a snack whenever I walk past them, too.
Even if the tops die off in my zone, they should be hardy enough to grow back from the roots.
Hopefully next year!