Grower and Executive Director
The Crape Myrtle Trails of McKinney
The most difficult step in the propagation of crape myrtles is keeping each variety true to its type. Being able to identify a dormant young plant or hardwood cutting is next to impossible, so correct and efficient labeling is the most important part of getting new plants started.
Propagation of crape myrtles can be accomplished in several ways, but hardwood cuttings and softwood cuttings are the preferred methods.
(Note that asexual propagation of those few patented crape myrtle varieties without written permission of the holder of the patent is illegal.)
Hardwood cuttings are taken in early winter after the leaves of the trees have fallen. Cut several 2- to 6-foot branches of the same variety, being careful to keep each variety identified and bundled together. Mark the bottoms of the branches if there is any question as to which ends were the basal ends. Cuttings that are inserted upside-down will not root.
Hardwood cuttings must have a dormant storage period. Pack them in sawdust or dry peat moss in a cool, dry location. In early spring, these branch cuttings will be removed from storage. Cut the sticks into 6- to 8-inch cuttings and plant them into prepared beds directly in the ground or into 1-gallon pots filled with a good potting soil mix. Plant each cutting deeply enough that only 1 to 2 inches will be above the soil. Once again, be certain they are right-side-up and carefully label each cutting as to the proper variety.
Softwood cuttings are taken in late May or early June. The late spring and early summer growth of crape myrtles is most vigorous. These cuttings are taken from the new growth that is still green and soft. Make your 6-inch cutting just beneath a leaf node, again being very careful to label each variety and keep each separate from the other varieties. Remove the leaves from the bottoms of the cuttings leaving a couple of leaves on the top of each cutting. Stick these cuttings into a porous rooting medium such as half Canadian peat moss and half horticultural grade perlite.
The cuttings must be placed in an area of high humidity or under a greenhouse misting system in bright light. The roots should form quickly, probably in just two to three weeks. At that time, carefully transplant each individual plant into a 4-inch pot and allow it to continue to grow. You will probably need to repot it into a 1-gallon (or larger) container by fall.
These softwood cuttings are preferred by many growers. Taken at that time of year, the cuttings will have plenty of time to get established and endure the winter dormant period. Some growers prefer to put three cuttings into each pot to help the plants develop into multi-trunked specimens more quickly. However, that makes it all the more critical that you keep variety identification accurate.
For the record, if you have root sprouts coming up around a mature crape myrtle, or if they have emerged following transplanting of an old plant, those sprouts will be genetically identical to the mother plant. You can dig and transplant them during the winter dormant season to get new plants of the same type.