Ann - thank you for contacting the Loudoun County Extension Master Gardeners, We have consulted with Loudoun's Horticulturist and are recommending the following info for your review.

The top cited medicinal herbs for VA Forest farming are listed below.  This list was cross-checked with the Digital Atlas Flora of VA to identify herbs consider native to Loudoun County.   
Please see the Virginia Tech resources for additional information: https://ext.vt.edu/natural-resources/forest-farming.html

A forest farming crop distribution map: https://www.rootreport.frec.vt.edu/docs/RootReport2020.pdf

American Ginseng (Panax quinquefolius):
https://www.fs.usda.gov/nac/assets/documents/research/publications/2011ginsengforest.pdfhttps://www.wildflower.org/plants/result.php?id_plant=PAQU

Harvesting / Private Land Plants must be 5 Yrs of age or older: https://www.fws.gov/international/plants/american-ginseng.htmlhttps://www.ahpa.org/portals/0/pdfs/Virginia.pdf

Deer, turkey, voles, etc, would all be a challenge. With hard work and a good level planting site physical protections could be set up.

Common black cohosh (Actaea racemosa) also called black bugbane:
http://vaplantatlas.org/index.php?do=plant&plant=2625&search=Search#http://www.wildflower.org/plants/result.php?id_plant=HYCA

Mayapple (Podophyllum peltatum):  http://vaplantatlas.org/index.php?do=plant&plant=325&search=Searchhttps://www.wildflower.org/plants/result.php?id_plant=POPE

Blue cohosh (Caulophyllum thalictroides):

http://vaplantatlas.org/index.php?do=plant&plant=785&search=Search
https://www.wildflower.org/plants/result.php?id_plant=CATH2

Stoneroot (Collinsonia canadensis) also called Richweed:
http://vaplantatlas.org/index.php?do=plant&plant=2649&search=Search
https://www.wildflower.org/plants/result.php?id_plant=COCA4

Wild yam (Dioscorea villosa) - a Vine:
http://vaplantatlas.org/index.php?do=plant&plant=73&search=Search
https://www.wildflower.org/plants/result.php?id_plant=DIVI4

Wild Indigo (Baptisia sp) - many different species - two considered native to Loudoun:
Yellow Wild Indigo http://vaplantatlas.org/index.php?do=plant&plant=2563&search=Searchhttps://www.wildflower.org/plants/result.php?id_plant=BATI
Blue Wild Indigo http://vaplantatlas.org/index.php?do=plant&plant=2561&search=Search
https://www.wildflower.org/plants/search.php?search_field=Blue+Wild+Indigo&family=Acanthaceae&newsearch=true&demo=

False Unicorn (Chamaelirium Luteum) also known as Blazing Star, Devil's-Bit:
http://vaplantatlas.org/index.php?do=plant&plant=1194&search=Search
https://www.wildflower.org/plants/result.php?id_plant=CHLU

While Golden-seal is a likely candidate to be grown in VA, it is not considered native to Loudoun County:

http://vaplantatlas.org/index.php?do=plant&plant=2856&search=Search
https://www.wildflower.org/plants/result.php?id_plant=CHLU

Additional Resources: 

Videos: https://www.appalachianforestfarmers.org/
Production Guides: https://newcropsorganics.ces.ncsu.edu/herb/
VA Herbal Society: https://www.herbsociety.org/hsa-about/hsa-units-and-districts/hsa-units/hsa-virginia-commonwealth.html
American Herbal Products Association: https://www.ahpa.org/AboutUs/AboutAHPA.aspx

It is important to know if you are on private or public land. Any plant collection from National Forests requires the issuance of a permit by the U.S. Forest Service.

https://www.fs.usda.gov/detail/gwj/special places/?cid=fsbdev3_032584.

There are three wild herbs on the VA Endangered plant list but none of these at risk communities are in Loudoun County.   https://www.fws.gov/endangered/map/va-info.html

There are reports of Wild Ginseng being diminished based on over collected but it is not currently listed as endangered. VA's National Forests did not issue permits in 2021. 

https://www.fs.usda.gov/detail/gwj/news-events/?cid=FSEPRD516977 
https://ecos.fws.gov/ecp/species/3261

VCE's Extension Master Gardeners are not advising, recommending, or prescribing any herbs for medicinal use. 
We hope the info provided answered your question. A very interesting topic! 

Thanks for contacting us. - Becky