Begun in 1728 by the pioneering botanist John Bartram (1699–1777), this is America's oldest surviving botanical garden. Bartram, with his son William, introduced into cultivation more than 200 native plants from species up and down the East Coast. John became the royal botanist for King George III, and made a fortune selling plants to England. Today the 10-acre historical site along the river has lots of flowering shrubs and trees, including various azaleas, rhododendrons, and magnolias, and the Franklinia, a tree from south Georgia that became extinct in its native habitat and survived only because Bartram gathered it. Although there is almost always something flowering, the best time to come is in May and June, when the gardens are fragrant and filled with the lively chatter of birds. The original 1728 farmhouse still stands, and you can take a tour through its rooms, which have various exhibits, including Native American artifacts from the property dating back 3,000 years. Prince Charles's former gardener David Howard has taken on Bartram's garden as a pet project of sorts. A garden shop is open 10–4 Friday through Sunday. It's tucked down a driveway in an impoverished neighborhood of Southwest Philadelphia; drive or take a cab.