I'm not a flower person so I'm seeking help here.

I tilled a 40 feet by 4 feet stretch of land and would like to plant flowers there, preferably by seed. The land is very rich and moist. The area is shaded until noon. I'd like the plants to not be over 2 feet high. I live in the mid Atlantic area. Also, keep in mind it is mid June.

Any suggestion would be appreciated.