No matter where I go someone asks about pruning crapemyrtles. It’s been a few years since I addressed this topic so I think it is time to cover it again. Especially since this is the time of year many crapemyrtles are pruned.
Michael Dirr’s Manual of Woody Landscape Plants (6th Edition) lists 92 cultivars of crapemyrtles. They range in height from less than 2 feet to greater than 40 feet. Flower colors range from pink to lavender to purple to red to white. It is impossibe to list specific pruning guidelines for each cultivar. However, all cultivars can be grouped into three categories: shrubs, multi-trunk trees, and single stem trees. The category is often determined by how the plant was pruned at the nursery. Plants are usually pruned at the nursery based on their mature size. Cultivars that will grow less than 10 feet tall are often left multi-stemmed and pruned like a shrub with multiple branches all the way to the ground. Taller growing cultivars have either a single or multiple stems and are limbed-up to create small to medium trees. It is my professional opinion and personal belief that crapemyrtles should be purchased based on mature size and form needed for the planting site and pruning should follow the training begun at the nursery. What it boils down to is shrub or tree.
The severe pruning we see in the landscape is often on plants trained in the nursery to be a small tree. Once in the landscape these plants sometimes cross paths with untrained individuals directing or doing pruning. The result may be a topped crapemyrtle. We have all seen them. Some call this crapemurder but I have never seen one killed by it, so I’ll stick with topping.
Now lets review the problems with topping trees. Topping involves removing a major portion of a limb and leaving a stub. The stubs left often don’t have the ability to close wounds and may begin to decay. Topping a tree produces numerous, weak sprouts just below the cut that break over when blown or weighed down by rain, snow, or ice. Crapemyrtle topping produces numerous sprouts that are weighed down by the plant’s blooms and fruit alone. These limbs get in the way of mowing, doing other chores, and often block views.
Crapemyrtles are sometimes improperly pruned due to poor plant location. Some people are concerned about the view these plants block, especially in parking lots. But when topped, the flush of growth results in a more inhibited view. This severe pruning results in many suckers at the base of the plant that are difficult and time consuming to prune. You can create views through crapemyrtles by removing lower limbs and thinning to enhance the form as a small, open tree. Know the size of the crapemyrtle you are purchasing and place it in an appropriate location, that way it can grow freely without the added work of pruning. If planting a structure, place large growing varieties at least 15 feet from a wall.
Timing of crapemyrtle pruning has been a bit confused. Yes, they are pruned in the winter since they flower on new growth, but heavy pruning does not result in more flowers. Small shrub form crapemyrtles can be pruned to keep them that way. Larger growing tree form varieties should be pruned to remove suckers, dead branches, and crossing branches only. Basically limb them up and open them up. Once a plant gets above ten feet then let it grow up and keep the suckers, crossing branches, and low branches that obstruct views thinned out.
Summer pruning after flowering is finished should remove suckers at the base and possibly remove developing seed heads on small plants. The removal of seed heads reduces weight on the ends of branches and may prevent broken limbs. If you want to get a second set of blooms on crapemyrtles try deadheading them. This is a great technique to use on smaller plants that are easy to get to. As soon as the flowers fade prune just below each large cluster of flowers. New growth will be produced and another set of flowers will form.
Remember to select the right crapemyrtle cultivar based on the location you want to plant it and then prune to train it to the shape you want. Be careful whom you take advice or direction from when pruning. And by all means, don’t follow a practice you see someone else doing unless you know the reason they are doing it. If you have any questions about crapemyrtle selection or pruning call the Extension Master Gardeners at 902-1705. You can also email your questions to firstname.lastname@example.org. As always check out what is going on at the Pitt County Extension office related to gardening at http://pitt.ces.ncsu.edu.