Japanese stiltgrass is regarded as one of the most troublesome invasive species in the United States. It is commonly found invading forested areas; however, more recently it has been noted to be invading golf course roughs and out-of-play areas. The purpose of this study was to evaluate POST herbicide control of Japanese stiltgrass in golf course and highly maintained turfgrass facilities. None of the treatments provided >80% Japanese stiltgrass control 2 wk after treatment (WAT). At 4 WAT >80% Japanese stiltgrass control was observed with MSMA, MSMA + metribuzin, amicarbazone, and sethoxydim, whereas metsulfuron, pinoxaden, and imazapic provided minimum control. By 8 WAT, MSMA, MSMA + metribuzin, amicarbazone, and sethoxydim provided >98% control, whereas quinclorac, metsulfuron, pinoxaden, and imazapic provided no visible control. Thiencarbazone-methyl + foramsulfuron + halosulfuron-methyl, and sulfentrazone provided limited (≤60%) control. This study indicates that POST control of Japanese stiltgrass can be achieved with MSMA, MSMA + metribuzin, amicarbazone, and sethoxydim. Future research should include long-term control over multiple growing seasons, repeat applications of herbicides, and evaluation of herbicides in combination for increased and longer-term Japanese stiltgrass control.

Ecological impacts from invasive plants that have been identified include reductions in biodiversity, changes in resource cycling, and disruptions of ecosystem function. To mitigate these negative ecological impacts, managers work to remove invasive plants. However, removal does not necessarily immediately lead to a return to the uninvaded ecological state. Similarly, the accumulation rate of ecological impacts following invader establishment is almost entirely unknown for most species, hindering identification of optimal management times. The accumulation and loss (so-called legacy effects) of impacts following invader establishment and removal represent an “invasion shadow.” To begin to understand invasion shadows, we measured the changes in biotic and abiotic ecological impacts during establishment and following removal of the forest understory invader Japanese stiltgrass. We found that when the abiotic metrics were considered, seeded areas became more functionally similar to the invaded landscape and removed areas became more similar to the uninvaded landscape. However, while the plant community did not change in a 3-yr period during a new invasion, following invader removal, it became less similar to both the invaded and uninvaded landscape altogether, suggesting legacies. Surprisingly, all changes occurred almost immediately and persisted following invader establishment and removal. Our results show, at least in a 3-yr period, that ecosystems can respond to changes in invader abundance, and in some cases simply removing the invader could result in long-term changes to the resident plant community.