I Can Garden
Canadian gardening resource site by editor and Master Gardener, Donna Dawson. Includes a member's area, news, articles, book reviews, clubs, suppliers, pictures and links.
http://www.icangarden.com/

SeeMeGarden
Community of gardening enthusiasts sharing tips, advice, experiences, and knowledge covering many aspects of gardening.
http://www.seemegarden.com/

The Helpful Gardener: Garden Forum
A discussion forum for the home gardener. Members provide helpful answers for home gardening questions in a number of topics.
http://www.helpfulgardener.com/phpBB2/

GardenWeb
Community of gardeners offering a wide range of resources. Forums on a large variety of general and specialized topics, glossary of botanical terms, seed exchange, and plant directory.
http://www.gardenweb.com/

Garden Country
Message board for communing with other gardeners. Includes a butterfly garden guide, weed identifier, and e-cards.
http://www.gardencountry.com/

Garden Stew
Discussion forums on several gardening topics, as well as a few home improvement topics.
http://www.gardenstew.com/

You Grow Girl
Offers a young fresh twist on gardening information, tips and articles. Discussion forums and archives available.
http://www.yougrowgirl.com/

GardenWeb Australia
Hosts forums, garden exchanges, articles, contests and a plant database.
http://www.au.gardenweb.com/

Blossom Swap
Lively community of gardening enthusiasts, forums, plant and seed swaps, articles, gardening tips, and photographs.
http://www.blossomswap.com/

UKY Listserv: Gardens & Gardening
Worldwide community chats via an e-mail mailing list on a wide variety of topics including gardening. Archives online available to members of the list.
http://lsv.uky.edu/archives/gardens.html

GardenBanter
A web front to several usenet newsgroups, covering general, regional, and water gardening topics. Threads are displayed forum-style. Posting requires registering with the site.
http://www.gardenbanter.co.uk/

GardenBuddies.com
Forums and photo galleries covering many gardening topics, visited by an international audience. Archives of plant information.
http://gardenbuddies.com

Gay Gardener
Offers planting tips, gardening history, forums, quotes, and a monthly newsletter.
http://www.gaygardener.com

Homestead Garden
Online community focused on gardening with a simplified-living bent. Forums, a few articles, links to extension services, and printable journals and logs.
http://www.homesteadgarden.com/

Just Gardeners
Includes forums, articles, catalog reviews, and a plant and seed swap area.
http://justgardeners.com/

Hort.net: Archived Active Horticultural Mailing Lists
Maintains archives of about 30 gardening-related mailing lists, with a link to archives of additional now defunct lists.
http://www.hort.net/lists/

Tinker's Gardens
This site focuses on daylilies, providing articles on their cultivation and hybridization, as well as an database. Also provides discussions of some other flowers and vegetables. Most of the action is in the many forums.
http://www.tinkersgardens.com/

Northscaping
Information resources, e-zine, forums, and links of interest to Northern gardeners and landscapers (USDA hardiness zones 1-5). Includes a landscape plant search, articles, climatic data, and business locators.
http://www.northscaping.com/

PlantTraders
Online community of friends and gardeners, sharing experiences, plants, and seeds.
http://planttraders.ipbhost.com/

Rhen's Garden Club
Christian gardening and homesteading site, offering forums, gardening information, and links to other resources.
http://www.freewebs.com/rhensgardenclub/

Gardeners at Witzend
Family-friendly site offering gardening forums, members photo albums, and member-contributed links.
http://www.witzend.net/

Moosey's Country Garden Forums
Discussion forums, garden journals and photo galleries, with topics including tours, plant identification, roses, and chat.
http://forums.mooseyscountrygarden.com/

Grows on You
A free social network for gardeners that provides photo upload, gardening weblog and a feature to list plants.
http://www.growsonyou.com

Excuse the Weeds
A forum and the ability to browse members' gardens. Listing new gardens is only available to paying members.
http://www.excusetheweeds.co.uk

Gardens Monthly Magazine.
The website of Gardens Monthly magazine with an active forum for swapping ideas and solving problems.
http://www.gardening.co.uk

The Gardener's Forum
A very active gardening forum with members from around the world.
http://www.agardenersforum.com

Ask an Arborist
A forum for asking for advice on the care of trees, principally with a UK focus.
http://www.tree-care.info/ask

Garden World Discussions
A friendly and knowledgeable community of gardeners, happy to share their experience with those new to gardening.
http://gardenworld.proboards103.com/index.cgi