Northern Piedmont

The Northern Piedmont runs from the Hudson Valley down through eastern Pennsylvania and Maryland into northern Virginia, taking in Lancaster, Reading, the western suburbs of Baltimore, and the Washington exurbs. It is rolling farm country on limestone and shale, with better soil than the mountains to the west and a longer season than the ridges. Natives like heart-leaf foamflower, sweetbay magnolia, and Appalachian-tea suit that middle ground, handling both the clay and the humid summers.

Conditions: Rolling limestone and shale soils, 40–48 inches of rain through the year, warm humid summers, moderately cold winters.

Cities and areas: Lancaster, Reading, Baltimore, Frederick, Trenton, Leesburg.