The New Jersey Native Plant Society provides a list of nurseries to help you find native plants. I entered the list into a google interactive map to make is easy for people to see where the nurseries are in their bioregion so they can find the most local eco-type plants.
A plant is considered native if it has occurred naturally in a particular region, ecosystem, or habitat without human introduction. Native plants help the environment the most when planted in places that match their growing requirements. They will thrive in the soils, moisture and weather of your region. Native plants form plant communities and biological interactions with specific flora, fauna, fungi, and other organisms. For example, some plant species can only reproduce with a continued mutualistic interaction with a certain animal pollinator, and the pollinating animal may also be dependent on that plant species for a food source.
You can make a difference in local biodiversity by planting natives in even small areas like container gardens. One easy project to start with is planting banquet barrels for butterflies. In my area, I choose butterfly weed, swamp milkweed, liatris blazing star, monarda, wild bergamot and goldenrod. Putting these into a barrel or a small garden patch provides both a food and nectar source for pollinators.