The objectives of this research were to compare the effects of eastern redcedar (bark and wood), hardwood (bark and wood), pine bark nugget (bark), pine (bark and wood), eucalyptus (bark and wood), cypress (bark and wood), and red-dyed (bark and wood) mulches on emergence of large crabgrass, johnsongrass, common lambsquarter, and redroot pigweed and to determine the possible chemical effects of these mulches by treating seeds with mulch leachate before and after planting. In the first experiment, seeds were planted in pots and one of each mulch type was applied directly above seeds. In the second study the seeds were pre-soaked and watered with mulch leachate. Although interactions between mulch type and weed species occurred, mulch reduced weed emergence by an average of 79% compared to non-mulched pots with eucalyptus having the least effect of the mulches (average 50% reduction). Leachate treatments had less of an effect than mulch, but reduced weed emergence by 16% averaged across all treatments. Red-dyed mulch leachate lowered weed emergence by 41%, more than all other mulch leachate, while eastern redcedar leachate reduced emergence by 23%. Overall, the wood mulch treatments had beneficial effects of reduced weed emergence compared to not using mulch and the response was dominated by physical rather than chemical influences.