answer:My friend who lives and gardens in a small island in the San Juans just wrote and said: “We have up until *********. They still need the cold ground to do their thing properly. I often buy the year’s end at the tulip store on Dec. 1 then plant them sometime in the next two weeks.” All spring bulbs can be planted at the same time; deeper for the bigger bulbs. Do you have a hungry rodent population? If so, they LOVE tulips and croci.. Daffs have something toxic in the bulb, so the mice, voies, chipmunks avoid them.