Crape myrtles - Lagerstroemia species - have become popular in Central Florida landscapes. They're one of the few plants that produce colorful flowers during our hot summers. Once established, they require very little maintenance.
Many homeowners, though, severely prune them this time of year. The practice is so common, it's got a name: crape murder.
A couple of years ago, Steve Bender, senior garden writer for Southern Living magazine, wrote a great article about pruning crape myrtles. He starts it by saying, "Each Saturday morning after football season ends, legions of bored men armed with saws and loppers emerge from their garages to commit 'crape murder.' They needlessly reduce majestic crape myrtles to ugly stumps - in many cases, ruining them forever."
If you're cutting back your crape myrtle to keep it from getting too big for its space, you've got the wrong variety for the spot.
Some varieties mature into medium or large shrubs, while others grow into small- to medium-sized trees - if allowed to grow naturally. Tonto is a semidwarf variety that's less than 12 feet tall after 10 years; Sioux is a medium-sized variety less than 20 feet tall after 10 years; and Miami can be more than 20 feet tall after 10 years.
You may want to replace your oversized crape with one destined to better fit the space. For a list of varieties and their mature size, along with other characteristics, visit edis.ifas.ufl.edu/MG266 and scroll down to the fact sheet.
Gary Knox, a professor of environmental horticulture with the University of Florida and the author of that fact sheet, advises against annual or frequent hard pruning of crape myrtles. It can induce excess vegetative growth, basal sprouting, and fewer flower clusters, he says. It also spoils the beautiful winter branch structure and leads to an unsightly knuckled appearance where pruning cuts are repeatedly made in the same location.
However, it's fine to remove suckers - long, upright shoots - from the lower portions of main stems or from roots when using crape myrtles as trees.