Ask Mr. Smarty Plants

This is actually not an easy request.  Our Native Plant Database will generate lists of plants native to your area by doing a Combination Search for Pennsylvania.  When selecting herbaceous plants that grow in sunny conditions (which we assume your lawn is) that are less than one foot tall, it generates a list of only 14 plants.  If you select sun and part shade, there are more choices, most of which will actually be taller than 6 inches.

In addition to that challenge, most lawn mowers will cut your lawn closer to 3 or 4 inches than six, so you would actually have to "mow" with a string trimmer.  All the plants flower at the ends of their stems, so one miss and the flower is gone.

Sorry we cannot be more supportive of your idea ... most meadow wildflowers evolved in the tall grass prairie so they are taller to compete with the grasses.  If you want wildflowers in your lawn you will have to plant them in swaths that you can mow around.  Check out our database and do the Combination Search; you may find what you are looking for.