Then go as far away as possible from home to build your first buildings. The physician can bury his mistakes, — but the architect can only advise his client to plant vines.

Frank Lloyd Wright (1867-1959) American architect, interior designer, writer, educator [b. Frank Lincoln Wright]

Lecture (1930-10-02), “To the Young Man in Architecture,” Chicago Art Institute
    (Source)

Closing pieces of advice, #11. One of two lectures delivered at the Institute. While the lectures took place in 1930, they were collected in book form in 1931, which is usually the year they are cited to. Both were reprinted in Wright, The Future of Architecture (1953).

In an article during the lead-up to that book, "Frank Lloyd Wright Talks of His Art," New York Times (1953-10-04), Wright restated the advice, but turned around:

The physician can bury his mistakes, but the architect can only advise his clients to plant vines -- so they should go as far as possible from home to build their first buildings.

For more discussion of the origins and variations of this quotation, see: Quote Origin: The Architect Can Only Advise His Client to Plant Vines – Quote Investigator®.