You water it daily, you add a little fertilizer when the blooms start to fade, and wait patiently for new blooms to follow in their wake. Nothing happens. The plant is healthy, it continues to grow, but there are very few new flowers coming and it's starting to look like a foliage plant instead of a flowering plant.
Deadheading is the process of removing the dying blooms to encourage new flower growth. Most gardeners already know this, and practice deadheading regularly. More important than simply understanding that you need to deadhead your flowers is knowing why you need to, what happens if you don't, and what that translates to in other parts of the garden.
Plants are working with a limited amount of nutrients, sunlight, and water with which to grow. Annuals have to do all of their growth, flowering, and seeding in one year. So think about it this way, if you put a pansy seed in the ground the first thing it does is grow roots, stems and leaves; this is like a baby learning to eat before learning to walk or talk, the stems support the leaves which in turn reach to the nearest light source to feed the plant while the roots dig deep to support the growth and pull in nutrients from the soil. So your little plant has learned to feed itself, next it will try to reproduce (luckily babies don't get a jump start on this one). Most plants reproduce by exchanging pollen between flowers, so the pretty pansy flowers you select are actually the plants sexual organs. What lovely ovaries you have, little pansy! Your plant develops these sexual organs in an attempt to achieve pollination (or fertilization), once a flower has been pollinated the petals will die off as they are no longer necessary to attract bees and other pollinators, and the plant must redirect it's limited energies to growing seed from the ovaries at the base of the flower. Grow, fertilize, reproduce. This is the basic life cycle of a plant.
Where does the benefit of deadheading come in? Your plant grows, puts out flowers to reproduce, then... you pluck the flowers and soon to develop seeds with them. You have stopped the cycle, so the plant responds by trying again: reproduce! You pluck again before seed development. The flowers just keep coming as the plant struggles to meet the deadline of fall frost to have fully developed seed to grow the next season.
|Apple and hazelnut trees grown out of control, pruning helps keep trees healthy.|
Remember that a plant is working with a limited nutrient supply. Your apple tree or tomato may put on tons of flowers, but if they aren't able to pull up adequate nutrition from the soil and sun, the fruits that develop may be tasteless, small, or susceptible to pests and diseases. Far better to trim down excess branches or flowers and ensure that the crop that reaches maturity is of the best quality.
My dad's property has an apple tree that has probably been there for eighty years, it is beautiful in full bloom. Dad never pruned it, and insisted the fruits on it were not worth eating, several years ago one of the largest branches broke off and I helped him to remove it. I told him it needed to be pruned, by at least 1/3 of the branches. He was uncertain at first and was afraid it would harm the tree beyond recovery. Finally I convinced him and we took out all but the 3 largest branches, and a few smaller ones. The tree is still alive and I'm happy to report that the apples that year were some of the best he'd ever gotten from that tree. Deadheading, pruning and pinching plants are methods of removing growth that impairs the plant's ability to produce the very best that it can. Keep this in mind as you cringe and fret with pruning shears in hand.