Tending a garden has been collective therapy this year, and Luciano Giubbilei has doubled down with two. The plots are a few miles apart in the sleepy northeast corner of Mallorca, Spain, where Giubbilei bought a house three years ago. One, in the courtyard outside his front door, is on its way to maturity; the other, in a sloping field nearby, existed mostly in his head until this fall, when it was planted in warm, slightly humid soil, a fleeting combination on a Mediterranean island known for its desertlike climate.
Giubbilei…