It’s that time of year again when people begin pruning trees and shrubs in anticipation of spring growth. And AgCenter horticulturist Allen Owings is concerned people will prune their crape myrtles incorrectly.

Crape myrtles need only occasional pruning, Owings says.

“An unfortunate trend in crape myrtle pruning is to lop off the tops, which results in a crew-cut appearance,” he says, noting this type of extreme pruning is called pollarding, or, as Owings calls it, “crape murder.”

The lush growth that occurs at these cut sites appears vigorous but is actually structurally weak and more susceptible to fungal diseases such as powdery mildew, he says. And, improper pruning over several seasons results in unsightly large, swollen knobs that form where pruning is done each year.

Such pruning will shorten the life of a crape myrtle and destroy the natural beauty of the tree, Owings says.

It’s not true that crape myrtles need to be pruned that way to bloom well, he says.

“The flower clusters may be larger on pollarded trees, but the added weight on the ends of long branches causes them to bend over awkwardly, especially after rain,” Owings says. “And because the tree is smaller, it actually produces fewer flower clusters.”

Before pruning, study the tree carefully and determine what needs to be excised.

“If you can’t come up with a good reason to prune your tree, leave it alone,” Owings says.

There are some reasons for pruning including: eliminating crossed and rubbing branches; removing low branches; removing weak, thin branches from the inner part of the tree; trimming off old seed pods; creating a shapelier tree and keeping suckers removed from the base of the trunk.

You asked

Torpedo grass is in my pond. Is there anything I can do? — Eva

Torpedograss is a very difficult weed to manage because it has underground storage rhizomes that give the weed great ability to recover from most herbicides. Your only option would be repeated applications of aquatic formulations of glyphosate, such as Rodeo. It may take a year or more to get torpedograss under control. — Ron Strahan, LSU AgCenter turf specialist

Got a gardening question? Write to GardenNews@agcenter.lsu.edu.