Some Australian plants tolerate pruning and some don't but that's true for plants from anywhere in the world. As a general rule all shrubby plants will tolerate light pruning to develop a bushy shape as they are growing. Pruning of mature plants can, however, present problems.
There are plants which can be pruned back to ground level and which will regenerate quickly by sending out masses of new growth...this is a technique sometimes referred to as "chain saw therapy". Plants in this category include those which develop a lignotuber (a swelling at or below ground level from which new growth forms) such as many banksias, eucalypts, melaleucas and isopogons, to name just four. Others, including most callistemons and the popular Grevillea hybrids G."Robyn Gordon", G."Honey Gem" and G."Superb" also tolerate such treatment.
If in doubt, pruning back by about one third should not cause problems as long as there is plenty of green foliage remaining. Annual pruning directly after flowering is a sound rule to follow.
|Many callistemons and melaleucas respond to heavy pruning. This Callistemon "Captain Cook" shows vigorous regrowth after being cut back to near ground level. Photo: Brian Walters|
Callistemons (bottlebrushes) should generally be pruned after flowering with the exception of C.viminalis and its cultivars which have a weeping habit that can be damaged by pruning.