Remove the flowers once the plant has finished blooming. Removing the faded flowers not only results in a tidier appearance, it also stops the plant from putting its energy into seed production. Energy put into seed production often results in smaller bulbs the following year. Although some people remove the stem as well, you can leave it as it's beneficial for photosynthesis.
Leave the foliage in place and allow it to receive as much light as possible. It may look like the plant is going dormant, but in reality the bulb is growing as the foliage withers. Let the leaves remain so that they can make food to feed the bulb. The time it takes for the leaves to fully die back depends on several variables. As a general rule, you should let the foliage remain for at least a month after the plant has bloomed. There is no need to tie or bundle the foliage.
Apply fertilizer to the soil around the plant. You may apply either granular or liquid fertilizer in a 5-10-10 or a 10-10-10 formulation. Work granular fertilizer into the soil around the plant, being careful not to damage the bulb. According to the University of Illinois Extension website, spring flowering bulbs perform best when they have five tablespoons of fertilizer and two cups of bonemeal applied over a 10-square-foot area. Water the bed after applying fertilizer.
Remove the leaves and stem once they've turned yellow or brown. Compost the leaves or dispose of them with your yard waste. 1
Apply a layer of mulch over the dormant plants. This is especially beneficial for newly established plants, or those exposed to harsh weather conditions. Mulch may consist of a 2-inch layer of leaves, straw, peat moss or similar organic matter. Mulch provides insulation and protects the first tender tips of the foliage from being damaged by cold weather when they emerge in the spring.