Usually done with hand-held pruners, heading stimulates the buds just below the cut, encouraging dense growth. Heading is a more aggressive approach than pinching when you're shaping certain small shrubs and flowering perennials. Thinning cuts open up a plant and result in the least amount of regrowth. Because you remove a number of lateral buds along with the stem or branch, you're less likely to wind up with clusters of unwanted shoots than you are when you make heading cuts. Use hand-held pruners, loppers, or a pruning saw to make thinning cuts, depending on the thickness of the member being cut.
Shearing is really random heading.
It produces an outer layer of dense, twiggy growth from buds below the cuts. Shearing Shearing, customarily used to create a hedge or a bush with spherical or square form, is a form of heading that makes no attempt to cut back to a bud. However, because plants chosen for this treatment typically have many lateral buds close together, you'll usually end up cutting near a bud. Shearing stimulates many buds to produce new growth, so you'll be repeating the job regularly once you start. Since this method cuts right through leaves, it's best done on small-leafed plants, where damage is less noticeable.