Critter, it is definitely a challenge trying to keep ants from some hummingbird feeders (and sometimes bees and wasps too!) You might try smearing petroleum jelly (vaseline) on the hook or wire that the feeder hangs from. I finally bought the Humzinger feeder with the built in ant moat in the center that you fill with water ... no more ants! :)
A few plants that should do well in your area:
http://garden.org/plants/searc... blooms late spring and early summer.
http://garden.org/plants/searc... blooms all summer
If you scroll down this page a short distance there's a list of plants that should do well in your area, many that are attractive to Butterflies and Hummingbirds:
http://www.dcnr.state.pa.us/cs...
