GardenComposer.com is another site full of interesting gardening information.

GardenGuides.com  has Gardening tips and ideas, and informative articles, charts and graphs, and guide sheets for growing hundreds of plants from the resource libraries.
 

Link Reputation is a great resource for establishing quality links to other sites.

PlantSeeker.com is a free site devoted to horticulture where you can buy, sell, and trade plants from around the world by posting and managing your own Classified Ads.