Magnolia Society International
- A worldwide organization of gardeners, nurserymen and other people who are devoted to the appreciation and study of magnolias.
- http://www.magnoliasociety.org/

American Conifer Society
- Association for the development, conservation, and propagation of conifers, with an emphasis on those that are dwarf or unusual. Photo gallery, database, information about membership and journal.
- http://www.conifersociety.org/

British Conifer Society
- Organization for gardeners and collectors of ornamental, dwarf and rare conifers, owners and managers of arboreta and nurseries, and professional botanists. Photo gallery and database, excerpts from the journal.
- http://www.britishconifersociety.org.uk/