Once tulips have bloomed and the flower begins to fade, they enter a seed production stage. It is important to cut the fading flower off at this time to prevent seed production. The energy that goes into producing the seeds takes away from the energy required to store nutrients in the bulb for the following season's growth. Use a pair of scissors or pruning sheers to cut the flower stem off at the point where it branches out from the foliage. Compost or throw away the flower and stem. Do not leave them in the area; this is an invitation to pests and disease.
Do not cut off the remaining foliage or sheer it down to ground level. The foliage is responsible for producing the energy that is stored in the bulb for the following year's growth. Cutting the foliage back before it has naturally died often results in a lack of flowers or smaller, unhealthy blooms the following year.
Approximately six weeks after blooming has finished, the foliage will die back naturally. This is evident by yellow, wilted foliage. At this point, dig up tulips grown in areas with exceptionally harsh winters. Cut off any remaining foliage and dispose of the cuttings in a compost bin or throw them away. Rinse the bulbs and allow them to dry out on a layer of newspaper. Place the bulbs in a mesh bag and store in a well-ventilated, cool area. If you store the tulip bulbs in a refrigerator, keep them away from fruits and vegetables, as the methane gases released by the produce will damage the bulbs.
If the bulbs are going to overwinter in the ground, cut the dead foliage to ground level. Compost or throw away the dead foliage. Work bulb fertilizer into the soil around the bulbs. Follow the manufacturer's directions for proper fertilization. Do not allow the fertilizer to come into direct contact with the bulbs. Place garden markers over the spot, thoroughly water the area and cover it with a 3-inch layer of mulch. The mulch will protect the tulip bulbs throughout the winter and prevent the soil from heaving.