RESOURCES - native plants
pennsylvania native plant society
The Pennsylvania Native Plant Society advocates conservation of native plants and their habitats and promotes the increased use of native plants in the landscape
NATIVE PLANT DATABASE (ladybird johnson wildflower center)
An exceptional resource for information on native plants, including a state by state guide.
USDA PLANTS DATABASE
The PLANTS Database provides standardized information about the vascular plants, mosses, liverworts, hornworts, and lichens of the U.S. and its territories.
Missouri botanical garden - Plant finder
Another great database of plant information - note several search options including "attracts butterflies"