Organic mulches (leaves, pine nuggets, pine straw, grass clippings, and chipped limbs) were applied at depths of 10, 20, or 30 cm in a 3 × 3-m area around young pecan [Carya illinoinensis (Wangenh.) K. Koch] trees. These treatments were compared to an unmulched herbicide treatment and a common bermudagrass [Cynodon dactylon (L.) Pers.] sod. Trunk cross-sectional areas (TCSAs) of the mulched trees were larger than those of trees in the sod or unmulched plots and increased linearly as mulch depth increased. All mulches influenced TCSA similarly. Mean TCSA for mulched trees increased 14-fold compared to an increase of 8-fold for the unmulched trees and the sod in this 3-year study. Thus, common yard-waste mulches can be used effectively to increase growth of young pecan trees.