Unlike tulips or daffodils, summer bulbs are not hardy in U.S. Department of Agriculture Plant Hardiness Map zone 5. They must be planted in the late spring or early summer, when the soil has warmed, and then dug and stored in the fall. This is why summer bulbs are often called "tender bulbs."
Some summer bulbs are slow-growing and may be started indoors in March or April. Elephant ears, for example, need a long, hot summer to grow to their typical height of 3 to 4 feet. Starting them in a warm, sunny window gives them a jump on the short growing season in zone 5. Tuberous begonias and cannas also benefit from a head start.
Summer bulbs tolerate the first light frosts of the autumn, but they will freeze and turn to mush when temperatures turn frigid. Dig them in September or early October, dry them thoroughly and store them in open boxes of peat moss or vermiculite in a cool basement.