The effects of fall and winter pruning on cold hardiness of field-grown Lagerstroemia L. `Natchez' (crape myrtle) were determined. In the first year (1990-1991) pruning prior to January reduced cold hardiness estimates of `Natchez' crape myrtle by 3C compared to controls. In the second year (1991-1992) fall pruning also reduced cold hardiness estimates by 3C on the January and February test dates. Pruning in January or later is recommended for `Natchez' crape myrtle to assure maximum cold hardiness. Similar cold hardiness estimates of `Natchez' crape myrtle were obtained from field trials compared to lath tests conducted the previous year.