A poor horticulture practice in Louisiana and across the South involves one of our most beloved landscape trees. Each year, crape myrtles are pruned improperly.

Topping crape myrtle trees is commonly referred to by knowledgeable gardeners as crape murder. This results in a crew-cut appearance.

The lush growth that occurs at these cut sites appears vigorous but is actually structurally weak and is more susceptible to fungus diseases such as powdery mildew. Worse yet, when people prune improperly over several seasons, unsightly, large, swollen knobs form at the point where pruning is done each year.

Crape myrtles need only occasional pruning, in most cases, to obtain the desired landscape effect. But many times these plants are butchered for no good reason. We often encounter gardeners who think they are supposed to prune their crape myrtles severely. Nothing could be further from the truth. For the overwhelming majority of us, enhancing the natural shape of our crape myrtles is most appropriate.

To prune a crape myrtle properly, first decide if it needs to be pruned. As with any pruning project, you must have a specific purpose in mind before you begin. If you can’t come up with a good reason to prune your tree, leave it alone. If you do see something that calls for pruning, study the tree carefully and determine what needs to be pruned to accomplish the specific purpose you’ve identified.

Examples of appropriate reasons for pruning include eliminating crossed and rubbing branches; removing low-growing branches; removing weak, thin branches from the inner part of the tree; trimming off old seed pods; and creating a shapelier tree and keeping suckers removed from the base of the trunk. Avoid cutting back or shortening branches larger around than your finger, although cutting larger branches back to a side branch or to the trunk, when needed, is fine.

With its smooth, muscular trunks, peeling bark, filigree of leafless branches in the winter and exceptionally long blooming season in summer, the crape myrtle is rightfully popular here. Make sure you keep yours looking its best.

Pruning demo

Learn how to correctly prune crape myrtle trees from an expert. Join Jimmy Culpepper, retired state forester and community volunteer, at 10 a.m. Saturday at Independence Park in the Crape Myrtle Garden, 7950 Independence Blvd., for an hourlong, hands-on pruning demonstration.

Culpepper was chief of information at the Louisiana Department of Agriculture and Forestry, a leading force behind Project Learning Tree — an educational program for schoolchildren, helped organize the Louisiana Arborist Association, and is a licensed arborist and an advocate of using native plants in local landscapes.

It’s one thing to read how to prune a tree but it’s totally different to actually experience pruning a live specimen. This is what you will get to do with Culpepper as he teaches pruning principles and explains the reason for each pruning cut.

Pruning is both an art and a science, and Culpepper expertly defines how to get the most out of your trees. No experience (or tools) is necessary, and I guarantee an enjoyable experience. A five-page handout will be available to all participants. This event is free and open to the public.

Housecleaning time

Johnny Naylor reminds readers to make sure to clean their purple martin houses because birds are here and more are on the way.

Some simple tips follow: Clear any vines or shrubs from under the houses.

Though it is not unheard of for a colony to live with these conditions, they prefer uncluttered areas.

Ideally, you want to make sure your house is at least 40 feet away from any trees or cover that may be able to conceal potential predators like hawks. Kick the house sparrows and starlings out now to ensure you have plenty of room for incoming purple martins.

Terrariums workshop

Master Gardener Angela Wall will be conducting a workshop for kids and adults on March 16 at the LSU AgCenter Botanic Gardens, 4560 Essen Lane, in the Orangerie.

If there is a child in your life who is interested in plants and gardening, The Tiny Magical World of Terrariums Workshop is a fun-filled opportunity to learn about plants by creating a terrarium — a tiny world, complete with soil, plants and rain. Each participant (both child and adult) will go home with a completed terrarium that should be easy to care for and fun to grow.

Participants are encouraged to bring small smooth stones or small animal figurines to include in the terrarium.

Registration is limited, offered on a first-come basis and open to the public. So, don’t miss this opportunity by being the first to register for Wall’s special event.

Registration deadline is March 1. Registration is limited to 10 children and 10 adults. This includes 10 children, ages 8-10, who must be accompanied by one participating adult per child. The workshop will be from 9 a.m. to 11 a.m. and is $15 per person. To register, call Bob Souvestre at (225) 763-3990.

Ponds, gardens

The Deep South Koi and Pond Society and Harb’s Oasis are once again presenting their annual Tour of Ponds and Gardens. This year’s event will be May 18-19.

If interested in having your pond showcased on the tour, email a photo of your pond along with a description (including size, mechanics, fish and plants) to TigrGrad86@aol.com.

The number of ponds on the tour is limited, so submit your information today. Be sure to visit http://www.deepsouthkoi.org.

Got a gardening question? Write to Bob Souvestre, horticulturist with the LSU AgCenter, at Burden Center, 4560 Essen Lane, Baton Rouge, LA 70809, or email to bsouvestre@agcenter.lsu.edu, or call Master Gardeners at (225) 763-3990.