Answer: While deadheading might seem confusing, the bottom line is that you want to remove the spent flower head to stop the formation of seeds so the plant will continue to produce new flowers. Not all plants need to be deadheaded (these are sometimes referred to as self-cleaning). Impatiens and bedding begonias are examples of self-cleaning plants; they shed their flowers and continue to produce new flowers without assistance. However, tuberous begonias, those with large clusters of flowers, should be deadheaded in order to keep the plants looking attractive. Probably the easiest way to approach this is - if the plant looks unattractive because of spent flowers, pinch them off, along with a portion of stem. New stems will be produced at a leaf node or scar along the stem, below where you've pinched or pruned it. With geraniums, you can wait until the entire cluster has flowered before removing it, or you can snip away the spent flowers as they appear. Then, when the final flower is spent, cut the entire flower stem down to where it joins the main stem. Petunias will benefit from regular deadheading. Pinch out the spent flower along with some of the stem. Whatever stem is left will wither down to a main stem. This will encourage the main stem to branch out, producing one or two new flowering stems. The more you pinch petunias, the bushier they will become and the more their potential for producing new flowers.
Each plant is different, but you can expect that the stem that holds the flowers will die after the flowers die and can be pinched or cut away. Hope this sheds some light on the subject!
Q&A Library Searching Tips