Here's a check list for you to look at. Feeding has been with a high-nitrogen fertilizer. Bulbs are planted in a shady area. If planted in partial sun, longer.
Bulbs are in competition for food with other plants.
Bulbs are planted in an area with poor drainage. They do not do well where the water puddles. Plants infected with basal rot have green color loss on the leaves, malformed leaves, stems, and flowers - or all. Plant leaves were cut too soon or tied off the previous year. The bulbs should be watered for about this long after blooming.