Callistemon trees, commonly known as bottlebrush trees, are native to Australia, growing mainly along the eastern coast with ranges of callistemons scattered throughout the country. The trees are recognisable by their long, spiked blooms, which vary in colour from yellow to red. Though the Australian coasts are ideal for callistemons to thrive, you can grow the trees in many regions of the world. Aside from providing proper watering and light exposure, you can help your callistemon trees thrive through occasional pruning.
Remove any dead wood or decaying wood from the tree. Dead wood appears brown, while decaying wood generally feels soft compared to the rest of the wood on the tree. Remove decaying wood spots with a small diameter with pruning clippers and spots with larger diameters with a pruning saw.
Do not remove any other of the wood closest to the trunk of a callistemon tree, aside from the dead or decaying wood. According to the Australian National Botanic Gardens, Callistemon should receive only light pruning, which focuses on the tips of the branches, and does not destroy any of the more mature wood in the interior branches of the tree.
Prune the tree to keep it at a specific size, or to remove parts of the tree that obstruct normal activities. Cut away the tips of branches that point horizontally to limit the size, or branches that aim downward to allow people and animals space to walk beneath the tree. Remove as much of the branch as necessary to reduce the tree to a manageable size for your yard, up to the point where the foliage and flowers cease on the branch, but do not cut back any further.
Make your cuts on a callistemon tree during the summer after the tree has blossomed. If your tree does not need to be reduced in size or have any dead wood, cut only the flowers from the tree as they appear. If you cut away the flowers immediately after the tree blooms, the callistemon replaces the blooms with new buds, which encourages greater flower production.
Remove all of the branches on a callistemon that sit low to the ground if the tree fails to thrive during the summer months. Though heavy pruning is not normally advised, older specimens may benefit from being cut back to the trunk at the base level. Healthy callistemon trees replace the pruned branches with new wood.