American Brugmansia and Datura Society
- Offers culture information, searchable plant database, registry and photographs.
- http://www.abads.net/

Georgia Perennial Plant Association
- Organization of perennial gardeners in the state of Georgia presents information on meetings and membership, a featured plant section, and photo galleries.
- http://www.georgiaperennial.org/

Ranunculaceae Society
- Society based in Ireland focusing on gardening with plants in the buttercup family. Information about activities, publications, and membership, photo gallery, and plant of the month feature.
- http://homepage.eircom.net/~ranunculaceae/

American Hibiscus Society
- Includes membership information, publications, chapter locations, events, and links.
- http://www.americanhibiscus.org/

National Chrysanthemum Society
- Promotes the propagation and cultivation of the chrysanthemum and increase the bonds of fellowship among growers of the chrysanthemum.
- http://www.mums.org