North Carolina Extension Gardener Handbook
This is your go-to link for any information you are seeking about plants, trees, flowers, fruit, pruning, fertilizing, diseases, and so much more. It's an extensive website, easy to navigate, and full of valuable up-to-date information. 
FYI: This is the online version of the book used for the Macon County Master Gardener Class.

North Carolina Extension Gardener Plant Toolbox
The Plant Toolbox website is all about "finding" the right plant for the right spot in your garden.
Filter your search of their current 4,704 plants to find that perfect plant! For example, you could check off light, slope/bank, flower color, bloom time, mountain location (or piedmont or coastal), and native plant. The website would then provide the results. Both scientific and common names are used. All plant information is included. The more specific you are with the filters, the better your search results. There are dozens of filter options to select to pinpoint your search results.

North Carolina Native Plant Society

Here is the link to recommended native plants and trees. They have broken them down into categories. If you are interested in a particular category, click on the tab to see the plants. There are trees, shrubs, vines, ferns, grasses, ground covers and much more.

NC Invasive Plant Council
Click on the button to view a full list of North Carolina Mountain invasive plants. Trees, shrubs, herbaceous plants, vines and aquatic plants are listed. Each plant can be clicked for further information, photo and PDF fact sheet about how to get rid of these plants.