In article says...
I know next to nothing about flowers though. What would be a hardy,
colorful, gently scented, perennial flower that grows well in central
NJ soil, especially a relatively steep slope? (If nothing fits all
these specifics, feel free to match just a couple of them!)

Buy 1/2 or full pound of wildflower seeds. Mix the seed in fine sand. I
use 7 parts sand, 1 part seed. Walk around the area spread the mixture
on exposed soil and tamp it down with your feet.

I've had good luck buying seed from this place.

http://americanmeadows.com/bulk_mix.cfm

They have a Northeast mix for NJ but I have been told other mixtures can
grow as well. This year I'm experimenting with 3 different regional
mixtures here in Chicago.

BTW: You'll need to get this seed planted within the next few weeks.