Deadheading flowers on plants is done for a variety of reasons and as you would expect, not all plants are deadheaded the same way - or for the same reasons. For instance deadheading a rose is not the same as deadheading a pansy.
There are several basic reasons for taking the faded flowers off plants, and there are as many ways in which to do it - according to plant. In talking of deadheading plants, we include bedding plants; shrubs; perennials; herbs. Many plants in the garden will benefit from having their dead flowers removed; some will not!
Most flowering plants are deadheaded the same basic way; which is to simply to take the fading flowers off, to allow the energy that would otherwise go into seed production be used by the plant in producing more flowering and overall growth.
This is particularly important with young newly-planted fruit trees. It is tempting to reap the fruit as soon as possible by leaving the small fruit on the tree in the first year of planting. It is far more beneficial in the medium to long term, to remove the fruitlets before they develop, to allow all the young plant’s energy to be used in establishing the plant (tree).