http://gty.im/157475224

Most places have had a wet, mild spring and the bulb plants are doing well. By all means enjoy the daffodils and other spring bulbs that have been blooming, and cut some flowers for spring arrangements. However, leave the foliage alone until it starts to yellow, usually in late spring or early summer (May or June in most locales). After the foliage has yellowed it can be cut to ground level. If the foliage is removed too early (for example, when the grass is mowed for the first few times), there will be fewer blooms next year. If cut back too early year after year the bulbs will gradually lose vigor and decline. This is because the foliage is making sugar through photosynthesis, and sending this sugar down to the bulb for next year’s show. This applies to daffodils and other spring-flowering bulbs such as hyacinth, tulip and crocus.