Understanding the relationships between below- and aboveground plant community diversity and composition is essential for understanding plant-soil linkages and feedbacks. Here we examine the patterns of belowground plant species richness, evenness, community composition, and individual species relative abundance with soil depth in a rough fescue grassland. Plant taxa belowground were identified via next-generation sequencing of the trnL intron. We found weak positive below-aboveground concordance in plant species composition demonstrating a general similarity between aboveground and belowground communities. The positive relationship between below- and aboveground plant species richness was stronger within the A horizon than in the B horizon, indicating that some species avoided rootingmore deeply in the soil. For the most common graminoid species at the site, there was no evidence for depth-related rooting preferences for species of Carex (sedges) or Elymus (wheatgrasses), while the dominant native grass Festuca hallii preferentially rooted shallowly while the invasive grass Bromus inermis rooted more deeply. Differential rooting patterns among some of the dominant species suggests some degree of belowground niche differentiation may be important in structuring this plant community.