A non-profit organization dedicated to preserving the genus Hedera through education and promotion. Site offers contact information, species photos with descriptions, a classification system, care instructions, article collection, membership details, and a question answering resource.

International society based in Britain promoting the cultivation and conservation of hebes and other New Zealand native plants. Includes plant profiles and photos, FAQs, and links.

Devoted to the study of new and rare ornamental landscape plants. Includes an online source guide and plant encyclopedia.

Dedicated to the preservation, study, and dissemination of Passiflora.

Society home page with Sweet Pea and Rose trial results, flower show venue and reports.

An international horticultural club interested in the species of all the genera of the Geraniaceae Family.

Society for the enjoyment of plants in the geraniaceae family centered in California. Events, information about membership and the magazine, culture tip sheets, and a photo gallery.