Iowa Woodland Owners Association, IWOA
- Promotes conservation and management of natural resources and provides educational support to tree growers. Includes membership application, photographs, events, news and resource links. Located in Iowa City.
- http://www.iowawoodlandowners.org/

Trees Forever
- Organization aims to plant and care for trees and the environment. Overview of programs and activities, news, materials, events, volunteer opportunities and photographs. Headquarters in Marion.
- http://www.treesforever.org/

Iowa State Horticultural Society
- Founded in 1866 for the purpose of promoting and encouraging horticulture and its related interests in the state. Includes board of director list, information about membership, affiliate organizations, garden calendar and calendar of events.
- http://www.iowahort.org/

Iowa Native Plant Society
- Dedicated to preserving and promoting Iowa's native flowers, grasses, sedges, shrubs, and trees. Information about membership, excursions, newsletters, and a photo gallery.
- http://www.public.iastate.edu/~herbarium/inps/inpshome.htm

Iowa Bonsai Association
- Founded to promote appreciation and development of bonsai. Includes meeting schedule, calendar of events, list of officers, and an article about basic plant care. Located in Des Moines.
- http://www.iabonsai.org/