As homeowners refresh the yard for spring, the May edition of Gardening Gazette from Cornell Cooperative Extension of Livingston County has advice for taking care of spring flowering bulbs.
Do not remove foliage from spring flowering bulbs such as tulips, daffodils, and hyacinths until after foliage has yellowed. Removing foliage before it yellows reduces food production and thus bulb size. Smaller bulbs mean smaller or no blooms next year.
If your plants failed to bloom this year and had lots of foliage, most likely they need to be dug up and divided.