Many flowers benefit from old flower removal, or deadheading. Removing the flowers as they wilt improves the appearance of the plant and prevents it from forming seeds. Once a flower produces seeds, it often stops blooming. The seeds also can self-sow themselves so that additional plants germinate and grow in unwanted areas of the garden. The best methods for deadheading depends on the type of plant, but all plants need the flowers removed as soon as they begin to wither.
Grasp the stem of most plants 1/4 to 1/2 inch beneath the spent flower. Pinch off the old flower, leaving the stem in place. Dispose of the flower after removal.
Cut of the entire stem at its base where it emerges from the main plant on flowers that send up multi-flowering stalks, such as iris or lilies. Wait until all the buds along the stalk have flowered and wilted before removing the stalk.
Remove the stem of short-season bulbs such as tulips and daffodils after the flowers have wilted but before the seed head completely forms. Leave the foliage in place until it dies back naturally, as the leaves collect nutrients for the bulbs after blooming completes.