(Almost) Never Too Late to Plant Bulbs
Normally spring flowering bulbs (tulips, daffodils, hyacinths, crocus, etc.) are planted from September through November in the Northern Hemisphere. In my climate (USDA zone 3), however, the soil often freezes before the end of October and I’ve occasionally had to plant bulbs in the frozen ground. Fortunately, soil freezes on the top first before frost reaches any depth, forming essentially a thin crust of frozen soil over the still friable garden soil below. So I’ve found it fairly easy to simply break the frozen crust of soil like a sheet of thin ice and plant my bulbs.
However, if you know in advance that you won’t be able to plant bulbs until a very late date, you can put a thick layer of compost or leaf litter on planting site. Both give off heat and will prevent the ground from freezing until you are ready to dig. Even so, you really should plant your bulbs… by mid-January at the latest!