Ecologists have come to appreciate that plant genotype can affect the success of restoration efforts, but the role of plant symbionts has received less attention. Epichloë-type endophytic fungi (EF) grow in the aboveground tissues of most plants and occur systemically in 20–30% of all grass species. Despite the potential for EF to alter plant competitive hierarchies and to be lost under improper seed storage, they have yet to be considered as an important factor in plant restoration ecology. We surveyed EF infection frequency in 42 native and restored populations of the dominant Great Lakes dune grass Ammophila breviligulata. We also conducted a greenhouse experiment to compare effects of herbivory and drought on an uninfected Michigan population of A. breviligulata and the commercially available ‘Cape’ variety, which is commonly planted for restoration. Surveys revealed low levels of EF infection in natural populations in the Great Lakes region. ‘Cape’ nursery stock was 100% infected. In the greenhouse, the Michigan plants were more sensitive to grasshopper herbivory and drought than the ‘Cape’ plants. Our results suggest that the variety of A. breviligulata used in dune restorations possibly could alter plant and insect community dynamics due to differences in EF status, though further tests under field conditions are needed.