In the spring of 1787, Thomas Jefferson, then Ambassador of the United States to France, made a three-month trip in the west and south of France and to northern Italy.
Bordeaux, where he stayed from May 24 to 28, 1787, was a particularly important stage. He visited the most prestigious Châteaux of the Médoc and the Graves, including Château Carbonnieux, then owned by the Benedictine monks of the Abbey of Sainte-Croix.
In the park of the castle, there is today a pecan tree over 30 meters high and 4.50 meters in circumference: a historic monument. It’s age corresponds to the visit of Thomas Jefferson: 230 years old in 2017.

This tree has always been known to the owners of the château as « Jefferson’s pecan ». Even if its dimensions attest to its great age, the subject deserved to be researched more thoroughly in the papers of Jefferson because the archives of the château have disappeared. During the French Revolution, the estate was seized as national property and sold in 1791; it subsequently had a series of different owners.
At the request of Jane Manaster, author of a study on the pecan tree Pecans published in 1994 and reprinted by Texas Tech University Press in 2008, Juliegh Muirhead Clark, librarian at the Colonial Williamsburg Foundation, conducted research on the period of Thomas Jefferson’s stay in France, from spring 1784 to autumn 1789, to establish a link with this tree.
Thomas Jefferson’s travel journal is mainly devoted to his observations on the agricultural economy of the regions he visited and in particular to viticulture and wine, of which he was a great lover, but there is no mention of the pecan tree.
On the other hand, his correspondence from the years 1785 to 1787 contains repeated requests to his friends, in particular to James Madison (who will be President of the United States after him), to send boxes of 100 to 300 pecans « as fresh as possible, packed in sand.”

Thomas Jefferson, a disciple of agrarian doctrine, an agronomist himself, was in contact with well-known botanists of the time: Buffon and Christian Guillaume de Lamoignon de Malesherbes. Thomas Jefferson provided them with samples of the flora and fauna of North America and in particular seeds, notably oaks, maples, and pecans. In October 1804 he was appointed Foreign Associate of the French Academy of Agriculture.
In a letter of May 1786, Monsieur de Malesherbes thanked Jefferson for the supply of a box of pecans and specified that in his eyes the pecan tree was « one of the trees in America that it is most interesting to naturalize in Europe and that will have to be planted in the southern provinces, because those already planted 15 years earlier at his home (in Malhesherbes, near Paris) have endured extremely harsh winters without damage, but have not yet produced fruit.”

Thomas Jefferson’s interest in developing pecan culture and his planting experiments on his property in Monticello, Virginia are well known. It would be surprising if he had not taken a box of pecans with him for acclimatization in the regions he visited, as suggested by Monsieur de Malesherbes. For lack of convincing archives, this was only a hypothesis until Dr. Maria Monteros of the Noble Research Institute visited the site in 2019 to perform a bit of botanical detective work. The results of her study proved a genetic link between this tree and the variety of pecan tree Jefferson brought with him upon his visits to France. The details of her visit and findings are a fascinating read and add proof to the oral history that this is truly Jefferson’s Pecan.