What are some nice flowers/ shrubs that can survive the weather of PA?

You didn’t say what kind of sun the area in question receives….? Full/Part/Shade?

“most” shrubs do best in full sun…..Perennials are what you are looking for if you are wanting flowers to come back the following year.

You best bet might be to visit a local garden center (NOT Home Depot, Lowes, etc.) in your area. They will likely carry stock and have knowledge of what will work best in your region.

Korean Spice Bush AKA Viburnum.

Mountain Laurel grows in the woods there (state flower).

Roses do fine. Your annuals geraniums, begonias, your flowering bulbs,etc.

You are in zone 5 or 6. Look at some nursery catalogs on line and see what appeals to you, what they require for growing, (light amount, water and soil requirements, etc.) Then you can look for sales on shrubs in your local area stores and get ones likely to survive. You could start with Peonies as they are hardy and like the sun. Snowball bush, flowering almond, and lilac are easy enough ones to start with and are fine in your zones. This is a good time to plant shrubs.
http://henryfields.com/category.asp?c=12&x=14&y=7