It depends on the type of garlic you planted. Hardneck garlic will send up scapes. They are not really flowers, but they are great to eat. If yours didn't send up scapes, you probably planted softneck.

You should harvest them when 1/3 to 1/2 of the leaves have turned yellow and the plant looks like it's starting to die. Do not let all the leaves turn yellow/brown or your garlic will not store well.

Thanks for the info. i just bought from some guy at the market - hardy for quebec? yes. poor son - no garlic flowers. but i will be paying attention to get them out of the ground in good time.