I used to create a list of native plants sales in the area. It was a lot of work. Thank goodness the Pennsylvania Native Plant Society has started listing the sales.
I also included a list of books on native plant gardening for the United States and Canada.
Here you go.
via Plant Sales and Festivals – Featuring Natives – PA Native Plant Society
Free Plant Lists on My Blog
Summer into Fall Blooming Plants
Native Fruits and Berries for Birds
Books on Gardening with Native Plants
Spring Wildflowers of the Northeast: A Natural History by Carol Gracie
Native Plants of the Northeast: A Guide for Gardening & Conservation by Donald J. Leopold
Essential Native Trees and Shrubs for the Eastern United States: The Guide to Creating a Sustainable Landscape by Tony Dove
Native Plants for New England Gardens by New England Wild Flower Society
Native Plants of the Midwest: A Comprehensive Guide to the Best 500 Species for the Garden by Alan Branhagan
Gardening with Native Plants of the Pacific Northwest 3rd Edition by
Native Plants of the Southeast: A Comprehensive Guide to the Best 460 Species for the Garden by Larry Mellinchamp
The Drought-Defying California Garden: 230 Native Plants for a Lush, Low-Water Landscape by Greg Rubin and Lucy Warren
Landscaping with Native Plants of the Southwest 2nd Edition by George Oxford Miller
Native Plants for the Short Season Yard: Best Picks for the Chinook and Canadian Prairie Zones by Lyndon Penner
100 Easy-to-Grow Native Plants for Canadian Gardens by Lorraine Johnson