There are several goldenrod (Solidago) species natvie to South Central PA. They bloom with yellow flowers in late summer, hosting over 100 species of butterflies. Goldenrod will naturalize in dry, full-sun conditions. You can dead-head the plants before they release their seeds to slow down their spread. Depending on the particular species, goldenrods can be anywhere from 6" to 3' tall. They are commonly blamed for causing allergy problems, but this is just not true! They are deer resistant, drought resistant, and will tolerate clay soil. The showiest goldenrod is Solidago speciosa.
The National Wildlide Foundation lists the following varieties as being native to SC PA: bog (Solidago uliginosa var. linoides), early (S. juncea), giant (S. gigantea), gray (S. nemoralis var. nemoralis), hairy (S. hispida var. hispida), showy (S. speciosa var. speciosa), and zigzag (S. flexicaulis).
📷: Jennifer Anderson, hosted by the USDA-NRCS PLANTS Database
Other sources: MissouriBotanicalGarden.org