The many varieties of bottlebrush of the genus Callistemon get their name from their distinctive brush-shaped flowers. The hardy evergreens may be grown as shrubs or small trees depending on how they are pruned during establishment. In addition to pruning your bottlebrush tree for shape, light annual prunings help keep your plant looking healthy and promote new production of the vibrant flowers throughout spring and summer.
Establishment
Step 1
Train your shrub into a tree shape by cutting away foliage and small branches close to the base of the tree. Remove these branches gradually throughout the plant's first three years to promote a thick and strong trunk.
Step 2
Remove some or all of the branches from the shrub that form a narrow V-shape between the trunk and the branch, leaving branches with a wider angle and bark protruding from the joining point. Branches with V-shaped attachments are not as strongly connected as those with raised bark at the base.
Step 3
Develop the shape of your bottlebrush tree by cutting branches from different points to create a natural layering of branches. The ideal bottlebrush has branches reaching upward and outward to create the weeping effect of the flowers and foliage. Structural pruning to establish the shape of your bottlebrush can be performed any time throughout the year, but you may need to sacrifice flowers in the process.
Maintenance
Step 1
Remove any dead or diseased branches each year. Wipe your pruning shears down with rubbing alcohol between cuts to prevent spread of disease between branches.
Step 2
Thin the canopy of your tree by removing the smallest stems and branches from the outside of the foliage. Never remove more than 10 percent of live growth, as over-pruning will reduce the health of your tree.
Step 3
Prune off new growth as the flowers are finishing their bloom, taking care not to cut into the established portion of the plant with little foliage. Alternately, prune growth from the previous season during your bottlebrush's dormant season before new growth appears in the spring.
Tips and Warnings
- Propagate new bottlebrush plants from the branches pruned at ground level. Aim for branches spaced 6 inches apart along the trunk.
Things You'll Need
- Pruning shears
- Rubbing alcohol
