Vegetable gardens at Monticello, courtesy of Wikimedia Commons
Ten years ago, re-creating a period garden might have been considered a nerdy pursuit. Hell, garden-variety gardening was considered nerdy pursuit, until recently.
But if the New York Botanical Garden can be considered any sort of trendsetter (it is New York, after all), the next big thing may be not just heirloom seeds, but heirloom gardens. In the past year or so, NYBG has re-created poet Emily Dickinson's garden, as well as two of Monet's gardens at Giverny. It's unlikely most of us will get ambitious enough to re-create famous gardens wholesale (just to give you a sense of how ambitous, here's a plant list for Giverny), but creating a period or semi-historical garden can be kind of a fun challenge. Especially if, like me, you enjoy novelty but get sick of the hype around all the new plants that get trotted out at garden centers like clothes on a runway every spring.
Because historic gardening is not a mainstream thing, finding help and resources takes a little legwork, but that's half the fun. St. Louis actually has a number of great period gardens planted alongside county and state historical sites like the Conway House at Faust Park and the Valle House in Ste. Genevieve. If you do a lot of car traveling, you might want to check out this list from Victory Seeds, too. There are also lots of online resources out there, from historical garden layouts to seed suppliers including Monticello, which has been doing this historic plants thing for a while.
For inspiration, check out these beautiful tinted glass slides by early 20th century garden photographer, Frances Benjamin Johnston, recently posted to the Library of Congress' Flickr; Wash. U. Landscape Architecture professor Dorothee Imbert's wonderful books on early Modernist gardens, including The Modernist Garden in France; and this page on Medieval and Renaissance gardens. Also good stuff: heirloomroses.com, the Historic Iris Preservation Society, Old House Gardens, the Cloisters Museum & Gardens, Gertrude Jekyll (the voice of Edwardian gardening), and this collection of seed sources.