As spring-flowering bulbs go through the flowering process, keep three care tips in mind:
1. If practical, remove spent flowers with a scissors or a hand pruner. This allows the plant to conserve its energy for bloom the next year rather than using it to produce seed.
2. Allow foliage to die naturally — it is needed to manufacture food that will be stored in the bulb and used for next year’s flowers.
3. Don’t fertilize. The roots of these plants start to shut down after flowering. Fertilizer applied at this time is wasted. Instead, fertilize during the fall at the time bulbs are normally planted and again in the spring when new growth pokes out of the ground. (Ward Upham)
