Native to the warm regions of southern Asia, crape myrtles (Lagerstroemia spp.) first entered North America in southern British colonies around 1750. Today, crape myrtles are a quintessential shrub or tree species throughout the South. Winter hardy in U.S. Department of Agriculture plant hardiness zones 7 through 10, these deciduous plants grow well in the American South, Southwest and along the mild winter areas of the Pacific Coast.
Transplanting Time Frame
The best time to dig up a crape myrtle from the landscape and transplant it is from fall to early spring when the plant is dormant. Since crape myrtles grow in southern latitudes in the United States, the winters usually are mild but chilly and do not involve frozen soil. Planting in October or up until December is ideal, as the soil is still warm and moist; the roots can then establish and grow for several months before spring warms up and new leafy growth appears. Crape myrtles raised in containers may be planted any time of year since there's minimal disruption and loss of roots after sliding the plant from its nursery pot. If fall or winter planting isn't possible, very early spring -- March -- is the next best option.
The younger or smaller the crape myrtle plant, the easier it is to dig up, locate and successfully transplant. Dig as large of a root ball as physically possible. You want to preserve as many roots and intact soil, but the root ball can't be so large and heavy that it inhibits transport to the new planting hole. Place the lifted tree and root ball atop a thick canvas, and wrap the edges over the root ball to help shade it and preserve the soil. Rather than lifting and shaking the dug crape myrtle during transport, slide or drag the canvas on the ground to diminish any root ball disintegration.
Create a planting hole that is just as deep as the extant root ball on the dug-up crape myrtle plant, but two to three times as wide. Slide or gently lift the root ball and tree into the planting hole, spreading the roots evenly and broadly once placed. Back-fill the hole with unamended soil. The top of the root ball must rest at the same height or 1-inch higher than the top rim of the planting hole. Do not plant the tree too deeply, as it leads to root suffocation and increases chances for fungal diseases over the next few years.
Use the excess soil left over from the planting hole to create a low berm around the newly planted crape myrtle. This creates a shallow watering basin to catch irrigation water. Water the planting area immediately, allowing water to trickle downward to compact the soil and remove any air pockets. If the tree is wobbly or sited in a windy location, stake the tree to prevent leaning or tipping for the first year. Monitor the soil over the winter and spring, irrigating it as needed to maintain an evenly moist soil. Roots continue to grow as long as soil isn't frozen, bone dry or soggy. Irrigate the tree as needed to avoid stress from droughts for two years after transplanting. This encourages the best root regeneration as possible as the tree establishes itself.