The boxwood origin is discussed briefly in the link below.

If the specific cultivar is important to you why don't you give them a call and ask to speak to their garden manager who should be able to help you. It's quite possible that they have more than one cultivar of boxwood and he or she should be able to tell you which one is sold at the gift shop.

Carolyn

Here is a link that might be useful: Mt Vernon Boxwood

hello,
i'm a belgian boxwood collector,
i have over 220 different buxus and looking for people in USA who can exchange buxus with me

best greetings, wim

It would be interesting to know if Mount Vernon has actual documentation of boxwood planted there in Washington's day, and documentation of parterre designs, if any. Most boxwood thought to be colonial is actually early 1800s or Colonial Revival. As yet, documentation of boxwood planted before 1800 is present but sparse.

It's Buxux sempervirens, or English boxwood. A Google search for "mount vernon boxwood" would have answered this question in a few seconds

Here is a link that might be useful: George Washington's Mount Vernon

As to the question of whether there is documentation to prove that boxwood at Mount Vernon was planted by George Washington, the official website for George Washington's Mount Vernon describes his fleur-de-lis English boxwood garden as "well-documented." Washington kept meticulous records as well as correspondence and diaries about his estate, even during the most serious engagements of the Revolution and his presidency. He commented in his diary about his fleur-de-lis boxwood garden. This garden, which was in decline (it was over 2 centuries old!), has been renovated recently

Here is a link that might be useful: George Washington's Mount Vernon

As to the best location for English box, try the website for English Boxwood in Virginia (see below)

Here is a link that might be useful: English Boxwood in Virginia