Gabriela Hearst Makes Life Decisions Based on Two Things, Sustainability and Tarot Cards

LONDON — There’s nowhere more fitting for Uruguayan-born designer Gabriela Hearst to be on a panel talking about sustainability than Winfield House, the official residence of Jane D. Hartley, the U.S. ambassador to the Court of St. James’s, which has the largest private garden in central London after Buckingham Palace.

Hearst was conceived in a forest; growing up her mother showed her the spot where the deed was done. She’s…