Spring bulbs are planted in the fall. Depending on the type, they may bloom any time from February through June. Crocus, tulip, hyacinth, muscari (grape hyacinth), and narcissus (daffodil) are best-known. Allium comes in many forms, some blooming into June. For very early bloom try some of the smaller bulbs, such as Iris reticulata, Chionodoxa, Scilla sibirica (Siberian squill), snowdrops, and species tulips, such as kaufmanniana, tarda, and greigii.
Summer bulbs are planted in the spring after the last frost date and must be dug up and stored during the winter. Examples of summer-blooming "bulbs" are gladiolus, dahlia, canna, and begonia. CSU Fact sheet 7.411
