on a slope near the Magothy river in MD?

My brother is dealing with the understory of an oak wood, and is looking for low maintenance native plants and shrubs, no dense cover to harbor mosquitoes. Hardy, self-propagating, but not rampant.

I suggested blueberry, Carolina allspice and coast azalea (atlanticum). There looks to be some clethra already. Anything else?

I came up kind of short on the perennials. There is a damper area near the bottom.

Thanks.