The objective of this study was to determine the history, usage, and presence of the seeds of vetiver (Chrysopogon zizanioides (L.) Roberty) sporadically distributed in the temperate coastal area of the Uwa Sea region, southwestern Japan. The species identity was confirmed based on both molecular identification using DNA barcoding and analysis of spikelet morphology. According to local farmers, vetiver was initially introduced in the 1950s to protect the juvenile orange tree seedlings from sea wind and the terraced fields from erosion. Vetiver plants were mostly found on terraced farms and no individuals had escaped. Mown vetiver straw has been used extensively as mulch for orange trees and subsistence vegetable culture. Until recently, vetiver plants propagated by division have been transplanted in this region. Eighteen vetiver inflorescences collected from eight clones in three localities in 2017 were found to bear no seeds. These results suggest that these local vetiver accessions are probably non-weedy and can grow well in the temperate coastal areas of Japan.
