Variety of shrubs, use in landscape dictate how to prune
Pruning should take place only if it is needed. If the right plant
has been used in the right place, pruning may be unnecessary or
minimal. If the natural shape of the shrub is used as a guideline,
pruning know-how can be simplified. The speed at which shrubs grow
is another characteristic to watch.
Dwarf shrubs don’t grow much each year, so not much pruning is
needed. Heavy or incorrect pruning could weaken them or cause
damage that takes years to recover.
If small-, medium- and large-size category shrubs have been used
correctly in the landscape, they too, may not need much pruning.
Shrubs that grow rapidly may need annual pruning to keep their form
dense and maintain flowering and fruiting. Formal hedges and
topiaries may need frequent pruning depending on how fast they
grow.
Flowering shrubs should be pruned based on when they bloom.
Spring-blooming shrubs should be pruned lightly when their flowers
begin to fade. Spring bloomers form their flower buds on previous
season’s growth, so dormant-season pruning reduces flower buds.
Waiting until after peak flowering to prune Indian hawthorn, Texas
mountain laurel and spirea can maximize the flower show.
Source: My West Texas