Keith Nevison at Thomas Jefferson's Monticello tells us that
Sweet William catchfly (Silene armeria) is particularly splendid in Monticello's gardens right now as we experience early summer weather. This very showy, self-seeding annual has bluish-green leaves and bright pink to purplish-pink flowers. It was established in American gardens by the 1820s and offered in the 1804 broadside by Philadelphia nurseryman Bernard McMahon (one of Thomas Jefferson’s gardening mentors).
