Removing dead flowers, or deadheading, is a good gardening practice. It may make plants produce extra flowers, it makes for a neater garden, and it prevents self-sown seedlings from popping up everywhere. To deadhead, pinch back to the next flower, bud, or leaf on a stem. On flowers such as petunias, pinch back the flower stalk to the first set of leaves below the bloom. If you simply pull off spent petunia petals, for example, you may leave behind the developing seedpod. Irises need a different method, because they produce new flowers lower on their stalks. Wait until all the flowers on a single stalk finish blooming, then cut the entire stem as close to the plant's base as possible.