Deadheading is a good method to channel a plant’s energy away from spent or nearly spent flowers into new growth. It is not harmful for plants and can encourage new blooms to develop. The exact method and technique will vary depending on the plant and its eventual purpose, but a good pair of sharp, clean shears will be a very useful tool. For example, if you are growing roses for the rose hips, you would not deadhead the plant. But if you are growing roses for the flowers, you would deadhead it to encourage new flowers to bloom.
Deadheading works best for ornamental plants. For many edible plants, you want the fruit to develop fully (ex. tomatoes), or you want to pinch off any flower buds as they start to form (ex. basil). We deadhead marigolds, and edible flowers like violas to encourage more blooms to form
Cover Image by sfbaywalk, used under its Creative Commons license.