when can spring flowering bulbs be put into the ground?

I assumed that one didn't plant bulbs too soon as extended warm weather might cause them to grow and break ground. But if that was the case then why wouldn't previously planted bulbs be similarly affected?

So for a zone 5 climate when is the soonest one can plant spring flowering bulbs?

Ground temp is the key. Your bulbs will do best if you wait until the soil is in the mid 50's but before you have a hard freeze. Some say 60, but I think that is still warm if you can wait. I don't plant until November or later, but as the bulbs arrive way before that, I store them in a cool dark closet until we plant.Be sure to take the alliums, frits and other stinky type bulbs to a place where they won't leave an unpleasant surprise. I forgot once and it took a long time to get rid of the stink in the guest room closet. Planting latter also means we have ample time to clean up all the beds before we plant the thousands that we put in each year. Best with your bulb planting from a bulb-a-holic. Patti