The evergreen bottle brush tree is one of 34 species in the Callistemon genus, according to the Australian National Botanic Gardens. The bottle brush tree grows best in warm climates and is cold hardy in zones 9 through 11 in the U.S. The bottlebrush, as it is known in Australia, can grow as tall as 15 feet with a spread of up to 15 feet. When pruned of spent flowers, the bottlebrush resembles the weeping willow tree.
Pruning the bottle brush tree is usually done for one of two reasons--to encourage the tree to reflower, or to provide clearance beneath the canopy. Decide how much of the branches will be removed by viewing the tree from a distance.
Trimming the tree in the fall after the tree has finished blooming is the best time to prune. Hold the spent flower in one hand and follow the branch back to a node (place where one branch connects). Cut close to the node with either the hedge clippers or pruning shears, depending upon the diameter of the branch to be cut.
Cut more of the branch if it hangs too low, is mangled, or is needed to shape the tree. Cut close to a node on the branch, up to one-third the length of the branch.
Prune older trees, in bad shape, back to ground level, if needed, to encourage new growth and blooms.
Load all limbs and branch trimmings into the wheelbarrow for disposal. Use a wood chipper to make mulch or dispose according to your local ordinances.
Cut off old flowers and seed pods back to the green leaves to encourage the summer blooms.
The bottle brush tree flowers with new growth. Pruning the new growth in the spring will mean sacrificing the summer blooms.