The butterfly bush, known botanically as Cassia bicapsularis, is a semi-tropical flowering perennial shrub that will grow nearly year round in the frost-free regions of Florida. The butterfly bush does not require regular pruning for health but can be made more attractive when pruned and groomed lightly and regularly. When grown in the middle and northern portions of the state, where frost occurs, the shrub will die back partially or entirely but regenerate in the following season.
Prune away any damaged, dead or broken branches or any branches that are drooping or lying on the ground. Prune back to a point of healthy wood, down to the parent branch or down to the main trunk, as desired. Deadhead spent blooms when they fade or begin to look untidy. Cut back the stem to just above a healthy pair of leaves.
Prune or pinch back the branch tips on the shrub throughout the late spring and summer to encourage branching and bushy fullness in the shrub. Remove just the terminal tips an inch or two down the branch.
Shear down the plant to the crown just a half inch or inch above the soil once the plant tissues are killed by frost. Removing dead tissues will prevent disease and insect breeding and will make room for new shoots in the spring.