It is hard to imagine by what power Washington could have mandated anyone grow anything after American independence in 1782, either as farmer/developer or as President.

In Washington's time, the greatest aspiration for any ambitious young man in the Virginia elite was to become a wealthy gentleman farmer. Washington was ambitious, and after he had married well, had a successful military career and did a couple of terms as President, he happily settled into farming at Mt Vernon and embarked on various different agricultural trials. One of those was to grow hemp, a commodity needed for the best rope and strongest canvas cloth. He tried it on all of the five Mt Vernon farms, but found it was not as profitable as growing wheat. So, what he did produce was used for making thread, cloth and rope for the farms' needs.

The folks at Mt Vernon have recently begun growing it again. https://www.mountvernon.org/george-washington/farming/washingtons-crops/george-washington-grew-hemp/