**4. Conclusions**

The rhizome essential oils of *C. aromatica*, *C. caesia*, *C. longa*, and *C. zanthorrhiza* that were cultivated in North Alabama showed wide variation in composition compared to essential oils from other geographical locations. Nevertheless, the essential oil yields and composition provide evidence that *Curcuma* can be successfully cultivated in North Alabama and may provide additional sources of these species for both culinary and herbal medicinal uses. The knowledge of their relative oil yields and composition could help in value-addition for either fresh rhizomes or dry herbal markets. The four species showed specific essential oil components, which are known to have extensive pharmacological activity separately or in combination with curcuminoids. The species can be used to tailor herbal medicines to combat particular ailments. The cultivation of specific varieties to cater to niche markets could not only benefit the farmers, but also have an impact on the socioeconomic sustainability of rural Alabama in particular and the southeastern U.S. in general. As far as we are aware, this is the first report of the essential oil compositions, including enantiomeric distributions for these *Curcuma* species cultivated in North America. Among the four species, the *C. longa* species that combine high yield with high curcumin have been found to be suitable for cultivation. However, the remaining species have economic potential, for example *C. zanthorrhiza* is well known for its antimicrobial activity against common human pathogens to cater to herbal companies interested in varieties that are high in a certain essential oil component.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/horticulturae8050360/s1, Figure S1: Gas chromatograms of rhizome essential oils of *Curcuma* varieties cultivated in North Alabama; Figure S2: Mass spectra of unidentified components of *Curcuma* rhizome essential oils.

**Author Contributions:** Conceptualization, S.R.M. and W.N.S.; methodology, L.D., S.R.M., P.S. and W.N.S.; formal analysis, S.R.M., R.S., P.S. and W.N.S.; investigation, L.D., S.R.M., R.S., P.S. and W.N.S.; resources, L.D. and S.R.M.; data curation, S.R.M. and W.N.S.; writing—original draft preparation, S.R.M. and W.N.S.; writing—review and editing, L.D., S.R.M., P.S. and W.N.S.; project administration, S.R.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** All data are available in the article.

**Acknowledgments:** The present work is a contribution of the Aromatic Plant Research Center (APRC, www.aromaticplant.org, accessed on 16 February 2022).

**Conflicts of Interest:** The authors declare no conflict of interest.
