I think that you will have a better chance of receiving a useful answer if you indicate the exact species you are interested in, and the quantity. A search in Google gives several hits for suppliers of small quantities of several species of Artemisia. They even seem to be available through Amazon!

Ask the Director, Central Institute of Medicinal and Aromatic Plants, Lucknow, India

www.cimap.res.in/‎

Thank you, Pedro and Debasis; Artemisia annua is the species of interest and the quantity can be between 5 and 10 kg.

This is a god place to get it: https://www.horizonherbs.com/group.asp?grp=499

Thank you, Andre.