When you say the last two years, are you counting this year as the second year, or is this the third year? Many hollyhocks are technically biennials, which means that the year you got it if it was blooming, then seedlings would come up the next year and grow a lot of leaves, then the year after that it'll bloom. So if this is the 2nd year, it should bloom this year but in your zone it may be a little early for them still (my hollyhock just started blooming very recently, and I'd expect yours to be a bit behind mine.) If this is what's going on, what you need to do is plant new blooming ones two years in a row, then they'll alternate, offspring of the first plant will bloom one year and offspring from the 2nd plant will bloom the other years.
Some hollyhocks behave as perennials though rather than biennial and if this is what yours is then there's something that's making it unhappy or else it should bloom every year. I have a perennial hollyhock and it blooms like a champ every year with absolutely zero attention (not even watering) from me so if yours is truly a perennial and it's not blooming then I'd look at whether it's getting enough sun, right amount of water, not being chewed on by some pest, etc. It may be hard to tell whether it's really a perennial or not since seedlings will come up in the same general area as the original plant, so it can fool you into thinking it's the same plant when it's really not. Mine is a huge one and I never cut the old stalks down so I always know exactly where the plant was the year before, and it always comes back in the exact same spot right around the old stalks, so I know mine's the same plant, but it's also the only plant in the last remaining neglected area of my garden, so it's very easy to tell, if you've got a much fuller bed I expect it'll be hard to tell if it's exactly the same plant coming back or not.
